Wireless communication method and wireless communication terminal using wake-up radio

ABSTRACT

Disclosed is a wireless communication terminal to communicate wirelessly. The wireless communication terminal includes: a first wireless transceiver configured to transmit and receive signals modulated by a first modulation method; a second wireless receiver configured to receive a signal modulated by a second modulation method different from the first modulation method; and a processor. The processor is configured to sequentially receive a plurality of fields of a wake-up radio (WUR) frame included in a WUR physical layer processing data unit (PPDU) transmitted by the second modulation method, and when a predetermined condition for the plurality of fields is satisfied, stop receiving the WUR frame without determining whether values of the plurality of fields are valid.

TECHNICAL FIELD

The present invention relates to a wireless communication method and awireless communication terminal using a wake-up radio.

BACKGROUND ART

In recent years, with supply expansion of mobile apparatuses, a wirelesscommunication technology that can provide a rapid wireless Internetservice to the mobile apparatuses has been significantly spotlighted.The wireless communication technology allows mobile apparatusesincluding a smart phone, a smart pad, a laptop computer, a portablemultimedia player, an embedded apparatus, and the like to wirelesslyaccess the Internet in home or a company or a specific service providingarea.

One of most famous wireless communication technology is wireless LANtechnology. Institute of Electrical and Electronics Engineers (IEEE)802.11 has commercialized or developed various technological standardssince an initial wireless LAN technology is supported using frequenciesof 2.4 GHz. First, the IEEE 802.11b supports a communication speed of amaximum of 11 Mbps while using frequencies of a 2.4 GHz band. IEEE802.11a which is commercialized after the IEEE 802.11b uses frequenciesof not the 2.4 GHz band but a 5 GHz band to reduce an influence byinterference as compared with the frequencies of the 2.4 GHz band whichare significantly congested and improves the communication speed up to amaximum of 54 Mbps by using an Orthogonal Frequency DivisionMultiplexing (OFDM) technology. However, the IEEE 802.11a has adisadvantage in that a communication distance is shorter than the IEEE802.11b. In addition, IEEE 802.11g uses the frequencies of the 2.4 GHzband similarly to the IEEE 802.11b to implement the communication speedof a maximum of 54 Mbps and satisfies backward compatibility tosignificantly come into the spotlight and further, is superior to theIEEE 802.11a in terms of the communication distance.

Moreover, as a technology standard established to overcome a limitationof the communication speed which is pointed out as a weak point in awireless LAN, IEEE 802.11n has been provided. The IEEE 802.11n aims atincreasing the speed and reliability of a network and extending anoperating distance of a wireless network. In more detail, the IEEE802.11n supports a high throughput (HT) in which a data processing speedis a maximum of 540 Mbps or more and further, is based on a multipleinputs and multiple outputs (MIMO) technology in which multiple antennasare used at both sides of a transmitting unit and a receiving unit inorder to minimize a transmission error and optimize a data speed.Further, the standard can use a coding scheme that transmits multiplecopies which overlap with each other in order to increase datareliability.

As the supply of the wireless LAN is activated and further, applicationsusing the wireless LAN are diversified, the need for new wireless LANsystems for supporting a higher throughput (very high throughput (VHT))than the data processing speed supported by the IEEE 802.11n has comeinto the spotlight. Among them, IEEE 802.11ac supports a wide bandwidth(80 to 160 MHz) in the 5 GHz frequencies. The IEEE 802.11ac standard isdefined only in the 5 GHz band, but initial 11ac chipsets will supporteven operations in the 2.4 GHz band for the backward compatibility withthe existing 2.4 GHz band products. Theoretically, according to thestandard, wireless LAN speeds of multiple stations are enabled up to aminimum of 1 Gbps and a maximum single link speed is enabled up to aminimum of 500 Mbps. This is achieved by extending concepts of awireless interface accepted by 802.11n, such as a wider wirelessfrequency bandwidth (a maximum of 160 MHz), more MIMO spatial streams (amaximum of 8), multi-user MIMO, and high-density modulation (a maximumof 256 QAM). Further, as a scheme that transmits data by using a 60 GHzband instead of the existing 2.4 GHz/5 GHz, IEEE 802.11ad has beenprovided. The IEEE 802.11ad is a transmission standard that provides aspeed of a maximum of 7 Gbps by using a beamforming technology and issuitable for high bit rate moving picture streaming such as massive dataor non-compression HD video. However, since it is difficult for the 60GHz frequency band to pass through an obstacle, it is disadvantageous inthat the 60 GHz frequency band can be used only among devices in ashort-distance space.

Meanwhile, in recent years, as next-generation wireless communicationtechnology standards after the 802.11ac and 802.11ad, discussion forproviding a high-efficiency and high-performance wireless communicationtechnology in a high-density environment is continuously performed. Thatis, in a next-generation wireless communication technology environment,communication having high frequency efficiency needs to be providedindoors/outdoors under the presence of high-density terminals and baseterminals and various technologies for implementing the communicationare required.

Particularly, as a mobile device including an embedded battery as apower source is spread and the use time of the mobile device becomesimportant, the energy efficiency of wireless communication terminals isalso becoming important. Therefore, there is a need for a wirelesscommunication method capable of increasing the energy efficiency of awireless communication terminal. In relation to the main method used toincrease energy efficiency in a wireless LAN, the wireless communicationterminal may enter the power saving mode when the wireless communicationterminal is not used. However, since the wireless communication terminalentering the power save mode does not perform wireless communication,wireless communication between the wireless communication terminal andthe external device may be restricted. Also, in order to receive awireless signal from an external device to the wireless communicationterminal, the wireless communication terminal may have to periodicallystop the power save mode. Accordingly, suggested is a method of awireless communication terminal to use a separate wake-up radio thattriggers the interruption of the power save mode. When the wirelesscommunication terminal uses the wake-up radio, the wirelesscommunication terminal includes a wake-up radio receiver for receiving awake-up radio at a low power. In the power save mode, the wirelesscommunication terminal may receive the wake-up radio through the wake-upradio receiver.

DISCLOSURE Technical Problem

An embodiment of the present invention is to provide a wirelesscommunication terminal using a wake-up radio.

Technical Solution

A wireless communication terminal to communicate wirelessly according toan embodiment of the present invention includes: a first wirelesstransceiver configured to transmit and receive signals modulated by afirst modulation method; a second wireless receiver configured toreceive a signal modulated by a second modulation method different fromthe first modulation method; and a processor. The processor isconfigured to sequentially receive a plurality of fields of a wake-upradio (WUR) frame included in a WUR physical layer processing data unit(PPDU) transmitted by the second modulation method, and when apredetermined condition for the plurality of fields is satisfied, stopreceiving the WUR frame without determining whether values of theplurality of fields are valid.

The predetermined condition may include a case where the wirelesscommunication terminal is not an intended recipient of the WUR frame.

The processor may be configured to determine whether the wirelesscommunication terminal is not the intended recipient of the WUR framebased on whether the WUR frame does not indicate an identifier of thewireless communication terminal as the recipient of the WUR frame.

The processor may be configured to determine whether the wirelesscommunication terminal is not the intended recipient of the WUR framebased on whether the WUR frame does not indicate an identifier of agroup including the wireless communication terminal as the recipient ofthe WUR frame.

The plurality of fields of the WUR frame may include a plurality ofreception terminal fields indicating a wireless communication terminalto receive the WUR frame, and the plurality of reception terminal fieldsmay be located in the WUR frame based on the order of the size of thevalue of the identifier of the wireless communication terminal indicatedby each of the plurality of reception terminal fields. The processor maybe configured to compare the value of the received reception terminalfield with the value of the identifier of the wireless communicationterminal and determine whether the wireless communication terminal isnot the intended recipient of the WUR frame based on a result of thecomparison.

When it is necessary to determine whether any one of the plurality offields is valid even if the wireless communication terminal is not theintended recipient of the WUR frame, the processor may be configured notto stop receiving the WUR frame.

The predetermined condition may include a case where the wirelesscommunication terminal does not support the reception of the WUR frame.

When the WUR frame has a length not supported by the wirelesscommunication terminal, the processor may be configured to determinethat the wireless communication terminal does not support the receptionof the WUR frame.

When the WUR frame has a length not supported by the wirelesscommunication terminal, the processor may be configured to determinethat the wireless communication terminal does not support the receptionof the WUR frame.

When the WUR frame is a type not supported by the wireless communicationterminal, the processor may be configured to determine that the wirelesscommunication terminal does not support the reception of the WUR frame.

When the WUR frame indicates a protocol not supported by the wirelesscommunication terminal, the processor may be configured to determinethat the wireless communication terminal does not support the receptionof the WUR frame.

When a predetermined condition for the plurality of fields is satisfied,the processor be configured to stop receiving the WUR frame withoutdetermining whether values of the plurality of fields of the WUR frameare valid through a frame check sequence (FCS) value generated based onthe values of the plurality of fields.

The processor may be configured to stop receiving the radio signalmodulated according to the second modulation method, and stop receivingthe WUR frame by transmitting a command for requesting to restart clearchannel assessment (CCA) from a medium access control (MAC) layer to aphysical layer.

A method of operating a wireless communication terminal for wirelesslytransmitting and receiving a signal modulated by a first modulationmethod, and receiving a signal modulated by a second modulation methoddifferent from the first modulation method according to an embodiment ofthe present invention includes: sequentially receiving a plurality offields of a wake-up radio (WUR) frame included in a WUR physical layerprocessing data unit (PPDU) transmitted by the second modulation method,and when a predetermined condition for the plurality of fields issatisfied, stopping receiving the WUR frame without determining whethervalues of the plurality of fields are valid.

The predetermined condition may include a case where the wirelesscommunication terminal is not an intended recipient of the WUR frame.

The stopping the receiving the WUR frame may include determining whetherthe wireless communication terminal is not the intended recipient of theWUR frame based on whether the WUR frame does not indicate an identifierof the wireless communication terminal as the recipient of the WURframe.

The plurality of fields of the WUR frame may include a plurality ofreception terminal fields indicating a wireless communication terminalto receive the WUR frame, and the plurality of reception terminal fieldsmay be located in the WUR frame based on the order of the size of thevalue of the identifier of the wireless communication terminal indicatedby each of the plurality of reception terminal fields. The stopping thereceiving the WUR frame may include comparing the value of the receivedreception terminal field with the value of the identifier of thewireless communication terminal and determining whether the wirelesscommunication terminal is not the intended recipient of the WUR framebased on a result of the comparison.

The stopping the receiving the WUR frame may include determining whetherthe wireless communication terminal is not the intended recipient of theWUR frame based on whether the WUR frame does not indicate an identifierof a group including the wireless communication terminal as therecipient of the WUR frame.

The stopping the receiving the WUR frame may include not stoppingreceiving the WUR frame when it is necessary to determine whether anyone of the plurality of fields is valid even if the wirelesscommunication terminal is not the intended recipient of the WUR frame.

The predetermined condition may include a case where the wirelesscommunication terminal does not support the reception of the WUR frame.

The stopping the receiving the WUR frame may include when the WUR framehas a length not supported by the wireless communication terminal,determining that the wireless communication terminal does not supportthe reception of the WUR frame.

The stopping the receiving the WUR frame may include when the WUR framehas a length not supported by the wireless communication terminal,determining that the wireless communication terminal does not supportthe reception of the WUR frame.

Advantageous Effects

An embodiment of the present invention provides a wireless communicationmethod using a wake-up radio and a wireless communication terminal usingthe same.

DESCRIPTION OF DRAWINGS

FIG. 1 shows a wireless LAN system according to an embodiment of thepresent disclosure.

FIG. 2 shows a wireless LAN system according to another embodiment ofthe present disclosure.

FIG. 3 shows a block diagram illustrating a configuration of a stationaccording to an embodiment of the inventive concept.

FIG. 4 shows a block diagram illustrating a configuration of an accesspoint according to an embodiment of the present disclosure.

FIG. 5 shows a process that a station sets an access point and a linkaccording to an embodiment of the present disclosure.

FIGS. 6 and 7 are diagrams illustrating a network including wirelesscommunication terminals supporting the WUR-based power save according toan embodiment of the present disclosure.

FIG. 8 is a diagram illustrating a format of a WUR PPDU according to anembodiment of the present disclosure.

FIGS. 9 to 10 show a specific format of a WUR frame according to anembodiment of the present invention.

FIG. 11 shows that a wireless communication terminal and a base wirelesscommunication terminal according to an embodiment of the presentinvention perform negotiations for WUR-related operations and performWUR-related operations.

FIG. 12 shows a format of a WUR capability element according to anembodiment of the present invention.

FIG. 13 shows a specific format of a PCR power saving WUR action frameand a specific format of a WUR mode element in a wireless communicationterminal according to an embodiment of the present invention.

FIG. 14 shows a specific format of a WUR disable action frame forstopping a WUR-based power save operation according to an embodiment ofthe present invention.

FIG. 15 shows a specific format of a WUR ID action frame according to anembodiment of the present invention.

FIG. 16 shows an operation in which a wireless communication terminalreceives a WUR beacon frame according to an embodiment of the presentinvention.

FIG. 17 shows an operation that a wireless communication terminal wakesup according to an embodiment of the present invention.

FIG. 18 shows a power save operation of a wireless communicationterminal according to an embodiment of the present invention.

FIG. 19 shows an operation in which a wireless communication terminalinterworking a WUR-based power save mode and a general power save modeaccording to an embodiment of the present invention.

FIG. 20 shows a WUR duty-cycle operation of a wireless communicationterminal according to an embodiment of the present invention.

FIG. 21 shows that a wireless communication terminal according to anembodiment of the present invention operates according to a More WURfield during a WUR duty-cycle operation.

FIG. 22 shows a method for a wireless communication terminal to receivea WUR frame according to whether a wireless communication terminalsupports receiving a WUR frame according to an embodiment of the presentinvention.

FIG. 23 shows a method of receiving a WUR frame according to whether awireless communication terminal supports reception of a WUR frame formatfor groupcast when the WUR frame received by the wireless communicationterminal according to an embodiment of the present invention is a WURframe for groupcast

FIG. 24 shows a method of receiving a WUR frame according to whether awireless communication terminal supports reception of a WUR frame formathaving a variable length when the WUR frame received by the wirelesscommunication terminal according to an embodiment of the presentinvention corresponds to a WUR frame format having a variable length.

FIG. 25 shows a method of receiving a WUR frame according to whether awireless communication terminal is an intended recipient of the WURframe when the format of the WUR frame received by the wirelesscommunication terminal according to an embodiment of the presentinvention has a fixed length.

FIG. 26 shows a method of receiving a WUR frame according to whether thewireless communication terminal is an intended recipient of the WURframe when the format of the WUR frame of the WUR frame received by thewireless communication terminal according to an embodiment of thepresent invention has a variable length.

FIG. 27 shows a variable-length WUR frame format according to anotherembodiment of the present invention.

FIG. 28 shows a WUR frame format when TXID is used according to anembodiment of the present invention.

FIG. 29 shows a WUR frame format when a group WUR ID is used accordingto an embodiment of the present invention.

FIG. 30 shows a method for a wireless communication terminal to receivea WUR frame according to a value of a More WUR field according to anembodiment of the present invention.

FIG. 31 is a flowchart illustrating an operation in which a wirelesscommunication terminal receives a WUR frame according to an embodimentof the present invention.

MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments of the present invention will be described belowin more detail with reference to the accompanying drawings. The presentinvention may, however, be embodied in different forms and should not beconstructed as limited to the embodiments set forth herein. Parts notrelating to description are omitted in the drawings in order to clearlydescribe the present invention and like reference numerals refer to likeelements throughout.

Also, when a part “includes” a component, this means that, unlessspecifically stated otherwise, it may further include other componentsrather than excluding other components.

FIG. 1 is a diagram illustrating a wireless communication systemaccording to an embodiment of the present invention. For convenience ofdescription, an embodiment of the present invention is described throughthe wireless LAN system. The wireless LAN system includes one or morebasic service sets (BSS) and the BSS represents a set of apparatuseswhich are successfully synchronized with each other to communicate witheach other. In general, the BSS may be classified into an infrastructureBSS and an independent BSS (IBSS) and FIG. 1 illustrates theinfrastructure BSS between them.

As illustrated in FIG. 1, the infrastructure BSS (BSS1 and BSS2)includes one or more stations STA1, STA2, STA3, STA4, and STA5, accesspoints PCP/AP-1 and PCP/AP-2 which are stations providing a distributionservice, and a distribution system (DS) connecting the multiple accesspoints PCP/AP-1 and PCP/AP-2.

The station (STA) is a predetermined device including medium accesscontrol (MAC) following a regulation of an IEEE 802.11 standard and aphysical layer interface for a wireless medium, and includes both anon-access point (non-AP) station and an access point (AP) in a broadsense. Further, in the present specification, a term ‘terminal’ may beused to refer to a concept including a wireless LAN communication devicesuch as non-AP STA, or an AP, or both terms. A station for wirelesscommunication includes a processor and a transceiver and according tothe embodiment, may further include a user interface unit and a displayunit. The processor may generate a frame to be transmitted through awireless network or process a frame received through the wirelessnetwork and besides, perform various processing for controlling thestation. In addition, the transceiver is functionally connected with theprocessor and transmits and receives frames through the wireless networkfor the station.

The access point (AP) is an entity that provides access to thedistribution system (DS) via wireless medium for the station associatedtherewith. In the infrastructure BSS, communication among non-APstations is, in principle, performed via the AP, but when a direct linkis configured, direct communication is enabled even among the non-APstations. Meanwhile, in the present invention, the AP is used as aconcept including a personal BSS coordination point (PCP) and mayinclude concepts including a centralized controller, a base station(BS), a node-B, a base transceiver system (BTS), and a site controllerin a broad sense.

A plurality of infrastructure BSSs may be connected with each otherthrough the distribution system (DS). In this case, a plurality of BSSsconnected through the distribution system is referred to as an extendedservice set (ESS).

FIG. 2 illustrates an independent BSS which is a wireless communicationsystem according to another embodiment of the present invention. Forconvenience of description, another embodiment of the present inventionis described through the wireless LAN system. In the embodiment of FIG.2, duplicative description of parts, which are the same as or correspondto the embodiment of FIG. 1, will be omitted.

Since a BSS3 illustrated in FIG. 2 is the independent BSS and does notinclude the AP, all stations STA6 and STA7 are not connected with theAP. The independent BSS is not permitted to access the distributionsystem and forms a self-contained network. In the independent BSS, therespective stations STA6 and STA7 may be directly connected with eachother.

FIG. 3 is a block diagram illustrating a configuration of a station 100according to an embodiment of the present invention.

As illustrated in FIG. 3, the station 100 according to the embodiment ofthe present invention may include a processor 110, a transceiver 120, auser interface unit 140, a display unit 150, and a memory 160.

First, the transceiver 120 transmits and receives a wireless signal suchas a wireless LAN physical layer frame, or the like and may be embeddedin the station 100 or provided as an exterior. According to theembodiment, the transceiver 120 may include at least one transmit andreceive module using different frequency bands. For example, thetransceiver 120 may include transmit and receive modules havingdifferent frequency bands such as 2.4 GHz, 5 GHz, and 60 GHz. Accordingto an embodiment, the station 100 may include a transmit and receivemodule using a frequency band of 6 GHz or more and a transmit andreceive module using a frequency band of 6 GHz or less. The respectivetransmit and receive modules may perform wireless communication with theAP or an external station according to a wireless LAN standard of afrequency band supported by the corresponding transmit and receivemodule. The transceiver 120 may operate only one transmit and receivemodule at a time or simultaneously operate multiple transmit and receivemodules together according to the performance and requirements of thestation 100. When the station 100 includes a plurality of transmit andreceive modules, each transmit and receive module may be implemented byindependent elements or a plurality of modules may be integrated intoone chip.

Next, the user interface unit 140 includes various types of input/outputmeans provided in the station 100. That is, the user interface unit 140may receive a user input by using various input means and the processor110 may control the station 100 based on the received user input.Further, the user interface unit 140 may perform output based on acommand of the processor 110 by using various output means.

Next, the display unit 150 outputs an image on a display screen. Thedisplay unit 150 may output various display objects such as contentsexecuted by the processor 110 or a user interface based on a controlcommand of the processor 110, and the like. Further, the memory 160stores a control program used in the station 100 and various resultingdata. The control program may include an access program required for thestation 100 to access the AP or the external station.

The processor 110 of the present invention may execute various commandsor programs and process data in the station 100. Further, the processor110 may control the respective units of the station 100 and control datatransmission/reception among the units. According to the embodiment ofthe present invention, the processor 110 may execute the program foraccessing the AP stored in the memory 160 and receive a communicationconfiguration message transmitted by the AP. Further, the processor 110may read information on a priority condition of the station 100 includedin the communication configuration message and request the access to theAP based on the information on the priority condition of the station100. The processor 110 of the present invention may represent a maincontrol unit of the station 100 and according to the embodiment, theprocessor 110 may represent a control unit for individually controllingsome component of the station 100, for example, the transceiver 120, andthe like. The processor 110 may be a modulator and/or demodulator whichmodulates wireless signal transmitted to the transceiver 120 anddemodulates wireless signal received from the transceiver 120. Theprocessor 110 controls various operations of wireless signaltransmission/reception of the station 100 according to the embodiment ofthe present invention. A detailed embodiment thereof will be describedbelow.

The station 100 illustrated in FIG. 3 is a block diagram according to anembodiment of the present invention, where separate blocks areillustrated as logically distinguished elements of the device.Accordingly, the elements of the device may be mounted in a single chipor multiple chips depending on design of the device. For example, theprocessor 110 and the transceiver 120 may be implemented while beingintegrated into a single chip or implemented as a separate chip.Further, in the embodiment of the present invention, some components ofthe station 100, for example, the user interface unit 140 and thedisplay unit 150 may be optionally provided in the station 100.

FIG. 4 is a block diagram illustrating a configuration of an AP 200according to an embodiment of the present invention.

As illustrated in FIG. 4, the AP 200 according to the embodiment of thepresent invention may include a processor 210, a transceiver 220, and amemory 260. In FIG. 4, among the components of the AP 200, duplicativedescription of parts which are the same as or correspond to thecomponents of the station 100 of FIG. 2 will be omitted.

Referring to FIG. 4, the AP 200 according to the present inventionincludes the transceiver 220 for operating the BSS in at least onefrequency band. As described in the embodiment of FIG. 3, thetransceiver 220 of the AP 200 may also include a plurality of transmitand receive modules using different frequency bands. That is, the AP 200according to the embodiment of the present invention may include two ormore transmit and receive modules among different frequency bands, forexample, 2.4 GHz, 5 GHz, and 60 GHz together. Preferably, the AP 200 mayinclude a transmit and receive module using a frequency band of 6 GHz ormore and a transmit and receive module using a frequency band of 6 GHzor less. The respective transmit and receive modules may performwireless communication with the station according to a wireless LANstandard of a frequency band supported by the corresponding transmit andreceive module. The transceiver 220 may operate only one transmit andreceive module at a time or simultaneously operate multiple transmit andreceive modules together according to the performance and requirementsof the AP 200.

Next, the memory 260 stores a control program used in the AP 200 andvarious resulting data. The control program may include an accessprogram for managing the access of the station. Further, the processor210 may control the respective units of the AP 200 and control datatransmission/reception among the units. According to the embodiment ofthe present invention, the processor 210 may execute the program foraccessing the station stored in the memory 260 and transmitcommunication configuration messages for one or more stations. In thiscase, the communication configuration messages may include informationabout access priority conditions of the respective stations. Further,the processor 210 performs an access configuration according to anaccess request of the station. The processor 210 may be a modulatorand/or demodulator which modulates wireless signal transmitted to thetransceiver 220 and demodulates wireless signal received from thetransceiver 220. The processor 210 controls various operations such asradio signal transmission/reception of the AP 200 according to theembodiment of the present invention. A detailed embodiment thereof willbe described below.

FIG. 5 is a diagram schematically illustrating a process in which a STAsets a link with an AP.

Referring to FIG. 5, the link between the STA 100 and the AP 200 is setthrough three steps of scanning, authentication, and association in abroad way. First, the scanning step is a step in which the STA 100obtains access information of BSS operated by the AP 200. A method forperforming the scanning includes a passive scanning method in which theAP 200 obtains information by using a beacon message (S101) which isperiodically transmitted and an active scanning method in which the STA100 transmits a probe request to the AP (S103) and obtains accessinformation by receiving a probe response from the AP (S105).

The STA 100 that successfully receives wireless access information inthe scanning step performs the authentication step by transmitting anauthentication request (S107 a) and receiving an authentication responsefrom the AP 200 (S107 b). After the authentication step is performed,the STA 100 performs the association step by transmitting an associationrequest (S109 a) and receiving an association response from the AP 200(S109 b).

Meanwhile, an 802.1X based authentication step (S111) and an IP addressobtaining step (S113) through DHCP may be additionally performed. InFIG. 5, the authentication server 300 is a server that processes 802.1Xbased authentication with the STA 100 and may be present in physicalassociation with the AP 200 or present as a separate server.

In a specific embodiment, the AP 200 may be a wireless communicationterminal that allocates a communication medium resource and performsscheduling in an independent network, such as an ad-hoc network, whichis not connected to an external distribution service. In addition, theAP 200 may be at least one of a base station, an eNB, and a transmissionpoint TP. The AP 200 may also be referred to as a base wirelesscommunication terminal.

In the doze state, the wireless communication terminal may stoptransmitting and receiving a wireless LAN radio and receive a wake-upradio (WUR) to increase energy efficiency. In this case, the magnitudeof the power used for the wake-up radio transmission and reception maybe smaller than the magnitude of the power used for the wireless LANsignal transmission. A general wireless LAN radio distinguished from theWUR may be referred to as a primary connectivity radio (PCR). A typicalwireless LAN may indicate a radio capable of transmitting and receivinga 20 MHz non-high throughput (HT) physical layer protocol data unit(PPDU) defined in IEEE 802.11. In addition, the wireless communicationterminal may enter a PCR doze state that blocks power supply to somefunctions including a PCR transmission/reception function. In the PCRdoze state, supplying the power blocked by the wireless communicationterminal again is referred to as PCR wake-up. Also, a state in which PCRtransmission and reception can be performed is referred to as a PCRawake state. The wireless communication terminal may stop the PCR dozestate and enter the PCR awake state to receive the PCR signal from anexternal device. In this case, the wireless communication terminal mayreceive the WUR signal and wake-up in the PCR doze state. This powersave operation is referred to as a WUR-based power save operation. ForWUR-based power save operation, the wireless communication terminal mayinclude a wake-up receiver (hereinafter referred to as “WURx”) thatoperates at a lower power than the PCR transceiver. In addition, whenthe wireless communication terminal needs to transmit a WUR signal, thewireless communication terminal may include a wake-up transmitter.Through the WUR-based power save operation, the wireless communicationterminal can reduce unnecessary wake-up operation. In addition, when WURis used, the time during which the wireless communication terminal staysin the PCR dose state may be increased.

A part of the WUR signal may be transmitted in a different modulationmethod than the modulation of the PCR signal. For example, a part of theWUR signal may be transmitted through On-Off Keying (OOK). Specifically,the PCR transceiver may transmit and receive modulated signals through awave-form modulation method using WURx and other wave forms.Hereinafter, an operation of a wireless communication terminal includinga WURx and a wireless communication method using WUR will be describedaccording to an embodiment of the present invention.

FIGS. 6 and 7 are diagrams illustrating a network including wirelesscommunication terminals supporting WUR based power save according to anembodiment of the present disclosure.

Referring to FIG. 6, the network may include an AP and a stationsupporting WUR based power save. The AP may transmit a WUR frame to theWUR terminal. Specifically, the AP may wake-up the terminal bytransmitting a wake-up frame to the WUR terminal. In the presentspecification, unless otherwise specified, a frame indicates a MACframe. Meanwhile, the AP and the station of FIG. 6 may include a PCRtransmission/reception function supporting at least one of802.11a/b/g/n/ac/ax, which is a general wireless LAN standard. Inaddition, the AP and the station in FIG. 6 may coexist in one networkand a general station that supports only PCR transmission/receptionwithout supporting WUR transmission/reception. For example, the networkof FIG. 6 may include a general station that does not have a WURfunction.

According to an embodiment, the AP may include a first wirelesstransceiver (TR) supporting a communication method using PCR. The firstwireless transceiver may transmit and receive PPDU through PCR. The APmay include a second wireless transmitter that performs WUR PPDUtransmission. The second wireless transmitter may be referred to as awake-up transmitter (WUTx). Here, a part of the WUR signal may be asignal transmitted in a second modulation method different from thefirst modulation method used in the PCR signal. Specifically, a part ofthe WUR signal may be transmitted through OOK. For example, the secondwireless transmitter may transmit the WUR PPDU to the station throughWUR. Also, if the AP additionally includes WURx, the AP may receive theWUR PPDU from the outside through the WURx.

Meanwhile, according to another embodiment, the first wirelesstransceiver and the second wireless transmitter may be implemented asone transceiver. For example, an AP may perform transmission andreception of a PCR signal and transmission of a WUR signal through onetransceiver.

As shown in FIG. 6, the AP may transmit the WUR PPDU including a wake-upframe that triggers a wake-up of the PCR transceiver of the station to astation that supports WUR-based power save. According to an embodiment,the AP may wake up only a station entering a WUR based power save modeamong a plurality of stations belonging to the AP's BSS. In addition,when the station receives a wake-up frame including an identifierindicating the station, the station may wake-up in the PCR doze state.For example, the WUR frame may include identification informationidentifying at least one station. The wake-up frame may includeidentification information identifying at least one station to wake-up.When the first station receives a wake-up frame including identificationinformation indicating the first station, the first station may wake-up.Also, a station other than the first station belonging to the AP's BSSor another BSS may not wake-up.

According to an embodiment, a station supporting the WUR-based powersave may include a WURx for receiving a wake-up frame. The station mayinclude a first wireless transceiver that supports PCR transmission andreception and a WURx, that is, a second wireless receiver that existsseparately. Here, the first wireless transceiver may be referred to as aPCR transceiver. The wireless communication terminal may transmit andreceive PCR signals using a PCR transceiver. Also, the second wirelessreceiver may receive a signal transmitted in a second modulation methoddifferent from the first modulation method of the signaltransmitted/received through the first wireless transceiver. The WURxmay receive a wake-up frame from the AP and wake-up the PCR transceiver.If the WURx receives a wake-up frame while the PCR transceiver of thestation operates in the PCR doze state, the WURx may wake-up the PCRtransceiver by using an internal wake-up signal.

For example, the station may have an interface between the PCRtransceiver and the WURx. At this point, the WURx may wake-up the PCRtransceiver of the station by using the internal interface.Specifically, the WURx may wake-up a PCR transceiver by transmitting aninternal signal to the PCR transceiver, but it is not limited thereto.For example, the station may have a processor that controls the overalloperation of the station. At this point, the WURx may wake-up the PCRtransceiver over the processor. Specifically, the station may cut offthe power supply of the PCR and the processor in the PCR doze state. Inthis case, the WURx may operate in a manner that stops cutting off thepower supply of the processor and wakes-up the PCR transceiver over theprocessor by receiving a wake-up frame.

According to an embodiment, the WURx may deliver information receivedthrough the wake-up frame to the PCR transceiver. The WURx may transmitinformation on subsequent operations following the wake-up to the PCRtransceiver by using the internal interface. Specifically, theinformation on the subsequent operations may be a Sequence ID (SID) thatidentifies each of the subsequent operations. In addition, PCR may setWURx parameters required for the WUR based power save operation by usingthe internal interface.

For example, the WURx may include a wake-up preamble detector (WUPreamble Detector), a wireless communication terminal identifierdetector (STA ID Detector), and a message parser. The WU preambledetector detects a wake-up frame by identifying a sequence of signalpatterns included in the wake-up frame. In addition, the WU preambledetector may perform automatic gain control (AGC) and synchronization onWUR based on the detected signal pattern sequence.

The wireless communication terminal identifier detector detects therecipient of the WUR frame. In this case, the recipient indicates arecipient intended by the wireless communication terminal that hastransmitted the WUR frame. In addition, the wireless communicationterminal identifier detector may obtain information identifying therecipient of the WUR frame based on the WU signaling field of the WURPPDU. In addition, the wireless communication terminal identifierdetector may obtain information identifying the recipient of the WURframe based on the WU preamble and WU signaling field of the WUR PPDU.The WU preamble and WU signaling field of the WUR PPDU will be describedlater with reference to FIG. 8. The message parser parses the messageincluded in the WUR frame. Specifically, the message parser may obtain amessage indicated by the WUR frame by parsing the message included inthe WUR frame.

According to an embodiment, the wireless communication terminal maydetermine a condition for maintaining the wireless communicationterminal in a state where WUR PPDU reception is possible through theWURx of the communication terminal. In a specific embodiment, thewireless communication terminal may maintain WURx to be available forreception until a certain condition is satisfied. For example, until thewireless communication terminal recognizes that the PCR transceiver ofthe wireless communication terminal succeeds in wake-up, the wirelesscommunication terminal may maintain the WURx in a state capable oftransmitting and receiving.

FIG. 8 is a diagram illustrating a format of a WUR PPDU according to anembodiment of the present disclosure.

The WUR PPDU may include a legacy part that the PCR transceiver iscapable of demodulating. Specifically, the WUR PPDU may be divided intoa legacy part that the PCR transceiver is capable of demodulating and awake-up part that the PCR transceiver is not capable of demodulating. Asdescribed above, the BSS may simultaneously include a wirelesscommunication terminal that supports WUR-based power save and a legacywireless communication terminal that does not support WUR-based powersave. In this case, it is necessary that the operation of the wirelesscommunication terminal supporting the WUR-based power save does notprevent the operation of the legacy wireless communication terminalexisting in the BSS.

Specifically, the legacy part may include a legacy preamble (L-Preamble)used in the existing 802.11 standard. Specifically, the legacy preamblemay include an L-STF including a short training signal, an L-LTFincluding a long training signal, and an L-SIG including signalinginformation for a legacy wireless communication terminal. The legacywireless communication terminal may determine the length of the WUR PPDUusing the legacy preamble. Accordingly, the legacy wirelesscommunication terminal may not access the frequency band in which theWUR PPDU is transmitted while the WUR PPDU is transmitted. Though thelegacy wireless communication terminal prevents interference withsignals including the WUR part following the legacy part.

In addition, the WUR PPDU may include a WUR symbol. For example, the WURsymbol may be one OFDM symbol following L-SIG. The WUR symbol may be anOFDM symbol modulated by a Binary Phase Shift Keying (BPSK) scheme. TheWUR symbol may include information indicating a BSSID. In addition, theWUR symbol may include information indicating the transmission type ofthe WUR part. For example, the transmission type may be unicast,multicast, or broadcast. When the transmission type is unicast, a WURpart to be described later may include identification informationindicating a wireless communication terminal to be waked up. In thiscase, the identification information may be an association identifier(AID) used in the PCR. Alternatively, the identification information maybe a WUR unique identifier (WUR ID) used in the WUR.

A wireless communication terminal supporting WUR-based power save candemodulate the WUR part through WURx. In this case, the WUR part mayinclude a wake-up preamble and a wake-up signaling part. The WURpreamble may include a signal pattern sequence indicating a WUR frame.Specifically, the base wireless communication terminal may insert apseudo noise sequence based on WURx modulation into the WUR preamble.The base wireless communication terminal can insert a pseudo noisesequence using OOK in the WUR preamble. The signal pattern sequence maybe a pattern applied equally regardless of a wireless communicationterminal receiving a WUR frame.

The WUR signaling field may be divided into a MAC header, a frame body,and a frame check sequence (FCS) field.

A wireless communication terminal supporting WUR-based power save mayparse the WUR signaling field of the WUR frame to determine therecipient of the received WUR frame. For example, the MAC header mayinclude an address field indicating the recipient of the WUR frame.Specifically, the MAC header may include a WUR identifier (WUR ID) thatidentifies a wireless communication terminal receiving a WUR frame. Whenthe wireless communication terminal receives a wake-up frame including aWUR ID indicating the wireless communication terminal, the wirelesscommunication terminal may wake-up the PCR transceiver. In order towake-up a PCR transceiver of a specific wireless communication terminalamong a plurality of wireless communication terminals included in theBSS using a wake-up frame, the base wireless communication terminal mayallocate different WUR IDs to the plurality of wireless communicationterminals, respectively.

According to one embodiment, when the wake-up frame triggers the wake-upof the PCR transceiver of a plurality of wireless communicationterminals, the MAC header of the WUR signaling field may include a groupidentifier (Group ID) that identifies a group including a plurality ofwireless communication terminals. Here, the Group ID may include a groupaddress (GA). Further, the base wireless communication terminal mayinsert subsequent operation information indicating a subsequentoperation of the wireless communication terminal to be the target ofwake-up in the MAC header of the WUR signaling field. For example, theWUR signaling field may additionally include a subsequent operationidentifier (SID) that identifies subsequent operations after wake-up.

For convenience of explanation, in the following, unless otherwisestated, it is assumed that the wireless communication terminal and thebase wireless communication terminal are a wireless communicationterminal and a base wireless communication terminal supporting WUR-basedpower save.

FIGS. 9 to 10 show a specific format of a WUR frame according to anembodiment of the present invention.

The MAC header of the WUR signaling field described through FIG. 8 maybe divided into a frame control field, an address field, and a typedependent control field. In this case, the Frame Control field indicatesbasic control information on the WUR frame. In addition, the Addressfield may indicate information on the address of the transmitter of theWUR frame or the address of the recipient. Specifically, the Addressfield may include at least one of information indicating the address ofthe transmitter of the WUR frame and information indicating the addressof the recipient. In addition, the Type Dependent Control fieldindicates variable control information changed according to the type ofthe WUR frame.

The Frame Control field may include information on the protocol versionfollowed by the WUR frame. In this case, a field indicating informationon a protocol version followed by the WUR frame may be referred to as aProtocol Version field. In addition, the Frame Control field may includeinformation indicating the type of WUR frame. In this case, theinformation indicating the type of the WUR frame may indicate whetherthe length of the WUR frame is a predetermined fixed length or variable.Or, information indicating the type of the WUR frame may indicate therole of the WUR frame. For example, information indicating the type ofthe WUR frame may indicate that the WUR frame is a WUR beacon. Further,information indicating the type of the WUR frame may indicate that theWUR frame is a wake-up frame. A field indicating information indicatingthe type of the WUR frame may be referred to as a Type field.

In addition, the Frame Control field may include a field indicating thelength of the WUR frame or a subtype of the WUR frame. When the lengthof the WUR frame is fixed, a field indicating the length of the WURframe or a subtype of the WUR frame may indicate a subtype of the WURframe. This is because when the length of the WUR frame is fixed, theWUR frame has a predetermined length. The field indicating the subtypeof the WUR frame may indicate whether the WUR frame is a WUR frame forunicast, a WUR frame is a WUR frame for broadcast, or a WUR frame is aWUR frame for groupcast. When the WUR frame is a WUR frame for unicast,the address field of the WUR frame may indicate a unique WUR ID. Whenthe WUR frame is a WUR frame for groupcast, the Address field of the WURframe may indicate a group WUR ID that identifies a plurality of WURwireless communication terminals. When the WUR frame is a WUR frame forbroadcast, the Address field of the WUR frame may indicate a broadcastWUR ID. A field indicating a subtype of the WUR frame may indicate thatthe WUR frame is a WUR beacon frame. In this case, the Address field ofthe WUR frame may include an identifier of the base wirelesscommunication terminal. Specifically, the Address field of the WUR framemay include the WUR ID of the base wireless communication terminal. Afield indicating a subtype of the WUR frame may indicate that the frameindicates a duty-cycle end. When the wireless communication terminalreceives a frame indicating the duty-cycle end, the wirelesscommunication terminal may determine that there is no WUR frame to betransmitted to the wireless communication terminal until On Durationcorresponding to the next transmission period. In this case, thewireless communication terminal may enter a WUR doze state that turnsoff the WURx when the WUR frame is received.

In addition, the Frame Control field may include information indicatingthat there is no additional WUR frame transmission to a terminaloperating according to a duty-cycle among terminals associated with thebase wireless communication terminal within a corresponding period aftera corresponding WUR frame. In this case, the absence of additional WURframe transmission may indicate that there is no additional wake-upframe transmission. Further, the absence of additional WUR frametransmission may indicate that there is no additional WUR beacon frametransmission. A field indicating information indicating that there is noadditional WUR frame transmission may be referred to as a More WURfield.

As described above, the Address field may indicate a unique WUR ID.Also, the Address field may indicate the group WUR ID. In addition, whenthe WUR frame is transmitted in a broadcast, the Address field mayindicate the identifier of the base wireless communication terminal.

The Type Dependent Control field may include information on a partialtiming synchronization function for time synchronization betweenterminals receiving a WUR frame according to the type of the WUR frame.In addition, the Type Dependent Control field may include informationindicating whether to change the BSS management parameter according tothe type of the WUR frame. In this case, information indicating whetherthe BSS management parameter is changed may be referred to as a BSSupdate counter. Also, when the WUR frame is a unicast wake-up frame, theType Dependent Control field may include information indicating how manyWUR frames the base wireless communication terminal has transmit to therecipients of the WUR frame. Information indicating how many WUR framesthe base wireless communication terminal has transmit to thecorresponding terminal may be referred to as packet number information.The packet number information may indicate how many WUR frames the basewireless communication terminal has transmitted to the recipients of theWUR frame in a circular counter format. When the base wirelesscommunication terminal successfully receives the response of thewireless communication terminal for the WUR frame, the base wirelesscommunication terminal may increase the counter value indicated by thepacket number information. When the WURx operation starts afterreceiving the wake-up frame and performing the PCR operation, thewireless communication terminal may store the counter value obtained byincrementing the counter obtained from the WUR frame. Also, the wirelesscommunication terminal may store the counter value obtained from the WURframe. In addition, when the packet number information of the WUR framedoes not indicate the counter value expected by the wirelesscommunication terminal, the wireless communication terminal may requestthe base wireless communication terminal to change the WUR ID of thewireless communication terminal. In this case, the wirelesscommunication terminal may transmit a frame requesting the WUR ID changeof the wireless communication terminal to the base wirelesscommunication terminal using PCR. When the packet number information ofthe WUR frame does not indicate the counter value expected by thewireless communication terminal, this is because the wirelesscommunication terminal may determine that the base wirelesscommunication terminal associated with the wireless communicationterminal has not transmitted the corresponding WUR frame. For example,the wireless communication terminal may determine that there is anexternal attack.

In another specific embodiment, the Type Dependent Control field mayinclude a TID or Access Category (AC) of data that the base wirelesscommunication terminal intends to transmit to the wireless communicationterminal together with a sequence number. In this case, the sequencenumber is the lowest number among the sequence numbers of the MACservice data unit (MSDU) corresponding to the TID corresponding to thehighest user priority among the TIDs of data that the base wirelesscommunication terminal intends to transmit to the wireless communicationterminal. In another specific embodiment, the sequence number maycorrespond to the TID corresponding to the highest user priority amongthe TIDs of data that the base wireless communication terminal intendsto transmit to the wireless communication terminal, and may be asequence number of an MSDU that successfully transmitted among the MSDUscorresponding to the TID. In a WUR doze state, the wirelesscommunication terminal may determine whether a WUR frame receivedaccording to the sequence number of the MSDU successfully received fromthe base wireless communication terminal for each TID is a WUR frametransmitted by a base wireless communication terminal associated withthe corresponding wireless communication terminal. In the Type DependentControl field, the number of bits in the field indicating the sequencenumber may be 12 bits.

In addition, the AC of the data may be the AC of the TID having thehighest user priority among the TIDs of data that the base wirelesscommunication terminal intends to transmit to the wireless communicationterminal. In the Type Dependent Control field, the number of bits of thefield indicating AC may be 2 bits. The TID of data may be a TID havingthe highest user priority among TIDs of data that the base wirelesscommunication terminal intends to transmit to the wireless communicationterminal. In the Type Dependent Control field, the number of bitsindicating the TID may be 3 bits. The value of the field indicating thesequence number of the Type Dependent Control field may be a partial bitof the sequence number. In this case, the value of the field indicatingthe sequence number may be a value corresponding to the number of bitsof the field indicating the sequence number from the least significantbit (LSB). The wireless communication terminal receiving the WUR framecan access the channel based on the AC indicated by the WUR frame. Inaddition, the wireless communication terminal receiving the WUR framemay determine a method of transmitting a response frame for datadepending on whether data corresponding to the TID indicated by the WURframe is transmitted in unscheduled-automatic power save delivery(U-APSD) mode or normal PS mode.

When the sequence number indicated by the WUR frame does not indicatethe sequence number expected by the wireless communication terminal, thewireless communication terminal may request the base wirelesscommunication terminal to change the WUR ID of the wirelesscommunication terminal. In this case, the wireless communicationterminal may transmit a frame requesting the WUR ID change of thewireless communication terminal to the base wireless communicationterminal using PCR. When the sequence number indicated by the WUR framedoes not indicate the sequence number expected by the wirelesscommunication terminal, this is because the wireless communicationterminal may determine that the base wireless communication terminalassociated with the wireless communication terminal has not transmittedthe corresponding WUR frame. For example, the wireless communicationterminal may determine that there is an external attack.

When the WUR frame is a WUR frame for groupcast transmission or a WURframe for broadcast transmission, the Type Dependent Control field maynot include packet number related information. In this case, the TypeDependent Control field may include Predictive Timer SynchronizationFunction (PTSF) related information instead of packet numberinformation. In addition, even if the WUR frame is a WUR frame forunicast transmission, when the More WUR field indicates that there is noadditional WUR frame transmission within a corresponding period, theType Dependent Control field may include PTSF-related informationinstead of packet number information. This is because the operation ofthe wireless communication terminal receiving the WUR frame may affectthe operation of other wireless communication terminals in duty cycleoperation.

When the WUR frame corresponds to a WUR frame format of variable length,the length of the Frame Body field may be variable. In this case, theType field may indicate that the length of the WUR frame is variable. Inaddition, the subtype field indicating the subtype of the WUR frame mayindicate the length of the Frame Body field. Specifically, the subtypefield may indicate the length of the WUR frame based on a predeterminedinformation unit, not a bit unit. For example, the Frame Body field mayinclude a plurality of subfields indicating information on each of theplurality of WUR wireless communication terminals. Specifically, theFrame Body field may include a first subfield indicating information onthe first WUR wireless communication terminal and a second subfieldindicating information on the second WUR wireless communicationterminal. In addition, one subfield may indicate information on aplurality of WUR IDs corresponding to the group WUR ID. When the FrameBody field includes a plurality of subfields indicating information oneach of the plurality of WUR wireless communication terminals, thesubtype field may indicate information on the length of the Frame Bodyfield using the number of subfields. For example, when the Frame Bodyfield includes subfields for each of the two WUR IDs, the subtype fieldmay indicate that the number of subfields included in the Frame Bodyfield is 2. When the WUR frame is a WUR Beacon frame and corresponds toa variable length WUR frame format, the Frame Body field may includeinformation related to management. In this case, the length of the FrameBody field may be indicated based on a predetermined information unit asdescribed above.

FIG. 9 shows a specific format of a MAC header of a WUR frame accordingto a specific embodiment of the present invention. FIG. 10 shows aspecific format of a MAC header of a WUR frame according to anotherspecific embodiment of the present invention.

The Frame Control field may include a Type field. The Type field mayindicate whether the WUR frame is a WUR beacon frame, a wake-up frame, aWUR discovery frame for discovering a BSS using WUR, or a vendorspecific frame. Also, the Frame Control field may include a LengthPresent field. The Length Present field may indicate whether thecorresponding WUR frame corresponds to a fixed-length WUR frame formatnot including the Frame Body field, or whether the corresponding WURframe corresponds to a variable-length WUR frame format including theFrame Body field.

In addition, the Frame Control field may include a Length/Misc field.The Length/Misc field may indicate the length of the WUR frame oradditional information other than the length of the WUR frame dependingon whether the WUR frame corresponds to the variable length WUR frameformat. Specifically, when the WUR frame corresponds to avariable-length WUR frame format, the Length/Misc field may indicateinformation on the length of the WUR frame. The information on thelength of the WUR frame may indicate the length of the WUR frame. Whenthe WUR frame corresponds to a variable-length WUR frame format, theLength/Misc field may indicate a length of 2 to 16 octets in units of 2octets. When the WUR frame corresponds to the variable length WUR frameformat, the Length/Misc field may indicate the length of the WUR framebased on a predetermined information unit. For example, the frame bodymay include a subfield indicating information on a wirelesscommunication terminal corresponding to the WUR ID for each WUR ID. Inthis case, the Length/Misc field may indicate the number of subfieldsincluded for each WUR ID in the Frame Body.

In addition, the Frame Control field may include a Protected fieldindicating whether the frame requires verification by a messageintegrity check (MIC). In this case, the Protected field may be a 1-bitfield. When the Protected field indicates that MIC is required, thewireless communication terminal receiving the WUR frame may checkwhether the WUR frame is valid using the MIC. When the wirelesscommunication terminal determines that the WUR frame is not validthrough the MIC, the wireless communication terminal may process the WURframe. The wireless communication terminal may discard the WUR frame.Specifically, when frame validation is required through the MIC, the FCSfield of the WUR frame may indicate a message integrity value. Thewireless communication terminal receiving the WUR frame may perform MICusing the encryption key previously received.

The Address field may indicate information on the address of thetransmitter of the WUR frame or the address of the recipient. Theidentifier included in the Address field may vary depending on the roleof the WUR frame. When the WUR frame is a WUR beacon frame, the Addressfield may indicate a transmission ID (TXID) that is an identifier of thebase wireless communication terminal. In addition, when the WUR frame isa wake-up frame for broadcast transmission, the Address field mayindicate TXID. In addition, when the WUR frame is a wake-up frame towake-up a plurality of wireless communication terminals corresponding toa specific group, the Address field may indicate the group WUR ID. Inanother specific embodiment, when the WUR frame is a wake-up frame forwaking up a specific plurality of wireless communication terminals, theFrame Body field of the corresponding WUR frame may indicate at leastone WUR ID among the plurality of wireless communication terminals. Whenthe WUR frame is a wake-up frame to wake-up a specific wirelesscommunication terminal, the address field may indicate the WUR ID of thecorresponding wireless communication terminal.

The WUR frame may include an FCS field indicating a value used tovalidate the WUR frame. The wireless communication terminal receivingthe WUR frame may determine whether an error is included in the processof transmitting and receiving the WUR frame based on the values of thefields included in the WUR frame and the values of the FCS field.Specifically, the wireless communication terminal receiving the WURframe performs a CRC operation based on the values of the fieldsincluded in the WUR frame to generate the FCS value, and compares thegenerated FCS value with the value of the FCS field. When the generatedFCS value and the value of the FCS field are the same, the wirelesscommunication terminal may determine that no error is included in theprocess of transmitting and receiving the WUR frame. When the generatedFCS value and the value of the FCS field are different, the wirelesscommunication terminal may determine that an error is included in theprocess of transmitting and receiving the WUR frame. The WUR frame maynot include the identifier of the base wireless communication terminal.Also, the WUR frame may be transmitted without being encrypted.Therefore, an external wireless communication device can copy the fieldvalue of the WUR frame and retransmit it. Through this, an externalwireless communication device can induce a power consumption by allowingthe wireless communication terminal to wake-up unnecessarily. In orderto prevent this, the following embodiments can be applied to a wirelesscommunication terminal and a base wireless communication terminal.

In a specific embodiment, the wireless communication terminal receivingthe WUR frame may perform the CRC operation to generate the FCS valueconsidering not only the values of the fields included in the WUR frame,but also the values of virtual fields not included in the WUR frame. Thewireless communication terminal may compare the generated FCS value withthe FCS field value. Therefore, the base wireless communication terminalmay also perform the CRC operation to configure the value of the FCSfield considering not only the values of the fields included in the WURframe, but also the values of virtual fields not included in the WURframe. In this case, the value of the virtual field may be a valuepreviously negotiated between the base wireless communication terminaland the wireless communication terminal. In addition, when there is noFrame Body field of the WUR frame, when generating the FCS value, thewireless communication terminal and the base wireless communicationterminal may consider that the virtual field is located after the MACheader. In addition, if there is a Frame Body field of the WUR frame,when generating the FCS value, the wireless communication terminal andthe base wireless communication terminal may consider that the virtualfield is located after the MAC header. The virtual field may be referredto as an embedded BSSID field. Through this operation, the wirelesscommunication terminal may determine whether the WUR frame includes anerror and also determine whether a WUR frame is transmitted from a basewireless communication terminal associated with the wirelesscommunication terminal. The specific format of the WUR frame may be thesame as that shown in FIG. 10.

For WUR-related operations, it is necessary to exchange information onwhether the base wireless communication terminal and the wirelesscommunication terminal support the WUR operations and to negotiate theWUR operations. The base wireless communication terminal and thewireless communication terminal may use PCR to exchange information onwhether to support the WUR operation and negotiate the WUR operation.This will be described with reference to FIG. 11.

FIG. 11 shows that a wireless communication terminal and a base wirelesscommunication terminal according to an embodiment of the presentinvention perform negotiations for WUR-related operations and performWUR-related operations.

The base wireless communication terminal and the wireless communicationterminal may exchange information on whether to support WUR operation ina link setup procedure. Specifically, the wireless communicationterminal may transmit a WUR capability element to the base wirelesscommunication terminal through a probe request frame, an authenticationrequest frame, and an association request frame. The WUR capabilityelement is an element indicating the capabilities supported by thewireless communication terminal in relation to WUR operation. Inaddition, the wireless communication terminal may transmit a WURcapability element to the base wireless communication terminal using aseparate action frame. In addition, the base wireless communicationterminal and the wireless communication terminal may transmit a WUR modeelement including information on WUR operation-related parameters in alink setup procedure. In addition, the base wireless communicationterminal and the wireless communication terminal may transmit WUR modeelements through an action frame. The WUR mode element will be describedin detail with reference to FIG. 12.

The wireless communication terminal may perform WUR-related operationsafter connection with the base wireless communication terminal. When thewireless communication terminal wants to enter the PCR doze state, thewireless communication terminal may transmit a WUR action frame to thebase wireless communication terminal. WUR action frames are exchanged toconfigure parameters related to WUR operation. WUR action frames can beexchanged through PCR. Further, the WUR action frame may request an ACKfrom the recipient of the WUR action frame. When it is determined thatthe base wireless communication terminal receiving the WUR action frameneeds to change or check the parameters related to the WUR operation,the base wireless communication terminal may transmit an additional WURaction frame to the base wireless communication terminal. The parameterrelated to the WUR operation may include at least one of a duty-cycleperiod and a length of on duration. The exchange process of the WURaction frame may be repeated until the configuration of parametersrelated to the WUR operation is completed. When the parameter agreementrelated to the WUR operation is completed, the wireless communicationterminal may change the power management mode to the power save mode andenter the PCR doze state.

When the wireless communication terminal of the PCR doze state receivesa wake-up frame indicating a WUR ID that identifies the wirelesscommunication terminal or a WUR ID that identifies a plurality ofwireless communication terminals including the wireless communicationterminal, the wireless communication terminal stores the informationindicated by the wake-up and turns on the PCR transceiver. Specifically,the wireless communication terminal stores the information indicated bythe wake-up and transmits a signal for turning on the PCR transceiver.When the PCR transceiver is turned on, the wireless communicationterminal may transmit information obtained from the wake-up frame to thePCR transceiver. In this case, the information obtained from the wake-upframe may include at least one of the packet number and TimerSynchronization Function (TSF) described above.

After PCR is turned on, the wireless communication terminal may transmita Wake-up (WU) response frame indicating that the wireless communicationterminal successfully wakes up to the base wireless communicationterminal. This is because the base wireless communication terminal needsto check whether the wireless communication terminal wakes upsuccessfully. Specifically, when a WUR frame is transmitted through WUR,1 bit is transmitted through one OFDM symbol. Therefore, thetransmission time of the WUR frame through WUR is very long. Inaddition, a wake-up delay (WUD), which is a time required to turn on aPCR transceiver in a PCR doze state, may also be a relatively long time.Therefore, even if the wireless communication terminal fails to wake up,when the base wireless communication terminal attempts transmissionthrough PCR, the wake-up process needs to be performed again and ittakes a relatively long time again until the wireless communicationterminal wakes up. The wireless communication terminal can reduce thetime required to transmit the WU response frame by transmitting the WUresponse frame using PCR rather than WUR. The wireless communicationterminal may transmit a WU response frame according to a channel accessmethod for PCR. The WU response frame may be a separate control framedefined for WUR operation. In addition, the WU response frame may be aframe used in an existing wireless LAN standard, such as a PS-pollframe. When the base wireless communication terminal wants to receive aWU response frame after designating a specific wireless time, thewireless communication terminal may attempt to access a channel fortransmitting a WU response frame after a corresponding time elapsesafter wake-up. In this case, the wireless communication terminal mayobtain information on a specific time through the WUR capabilityelement. As described above, the WUR capability element may betransmitted through a probe request frame, an authentication requestframe, and an association request frame. Also, the wirelesscommunication terminal may obtain information on a specific time througha WUR action frame.

The base wireless communication terminal receiving the WU response framemay transmit a WU Acknowledgement (ACK) frame to the wirelesscommunication terminal. The WU ACK frame may be an immediate responseframe. Specifically, the WU ACK frame may be an ACK frame. Further, theWU ACK frame may be a separately defined control frame for WURoperation. In addition, the WU ACK frame may be QoS data. The wirelesscommunication terminal receiving the WU ACK frame may perform generalPCR operation.

When the base wireless communication terminal does not receive a WUresponse frame from a time point that transmits a wake-up frame to apredetermined time, the base wireless communication terminal maydetermine that the wake-up of the wireless communication terminal fails.In this case, the base wireless communication terminal may transmit awake-up frame to the wireless communication terminal again. In order todetermine whether a predetermined time elapses, the base wirelesscommunication terminal may configure a timer after transmitting awake-up frame. The predetermined time may be a time longer than the sumof the WUD and NAVSyncDelay values of the wireless communicationterminal. NAVSyncDelay indicates a time during which the transmission ofthe wireless communication terminal is prohibited so that the wirelesscommunication terminal may configure the NAV based on a frame or PPDUtransmitted through PCR after wake-up.

In the embodiment of FIG. 11, the first WUR station WUR STA1 and thesecond WUR station WUR STA2, which are APs, perform a link setupprocedure. In this case, the first WUR station WUR STA1 and the secondWUR station WUR STA2 exchange WUR capability elements and WUR modeelements. In addition, the second WUR station WUR STA2 transmits a WURaction frame to the base wireless communication terminal to enter theWUR doze state. The first WUR station WUR STA1 and the second WURstation WUR STA2 exchange action frames to configure WURoperation-related parameters. When the first WUR station WUR STA1 hasdata to be transmitted to the second WUR station WUR STA2, the first WURstation WUR STA1 transmits a wake-up frame to the second WUR station WURSTA2. The second WUR station WUR STA2 receives the wake-up frame andturns on the PCR transceiver. In this case, it takes a time by WUD untilthe PCR transceiver is turned on. After the PCR transceiver is turnedon, the second WUR station WUR STA2 transmits a WU response frame to thebase wireless communication terminal. The first WUR station WUR STA1transmits a WU ACK frame to the second WUR station WUR STA2. Throughthese operations, the wireless communication terminal can enter the PCRdoze state and wake-up again.

The format of the WUR capability element described with reference toFIG. 11 will be described in detail with reference to FIG. 12.

FIG. 12 shows a format of a WUR capability element according to anembodiment of the present invention.

The WUR capability element may follow the format of the generalextension element of the 802.11 standard. Specifically, the WURcapability element may include an Element ID field, a Length field, andan Element ID extension field.

The WUR capability element may include information on WUD, which is atime required for the wireless communication terminal that transmits theWUR capability element to turn on the PCR transceiver in the PCR dozestate. This information may be referred to as wake-up delay information.The base wireless communication terminal transmitting the wake-up framemay determine whether the wake-up fails based on a time longer than thesum of time required for transmitting the WUD and WU response frames.Specifically, after transmitting the wake-up frame, the base wirelesscommunication terminal may configure a timer having a period longer thanthe sum of the time required for transmitting the WUD and WU responseframes. When the timer expires, the base wireless communication terminalmay determine that the wake-up fails.

The WUR capability element may include information on the time requiredfor the wireless communication terminal that transmits the WURcapability element to turn on the WURx. This information may be referredto as turn-on latency information. The base wireless communicationterminal may transmit a WUR frame to the wireless communication terminalin consideration of turn-on latency information. Specifically, the basewireless communication terminal may transmit a WUR frame to the wirelesscommunication terminal after the time indicated by the turn-on latencyinformation elapses from the time point at which the wirelesscommunication terminal enters the PCR power saving mode. Wake-up delayinformation and turn-on latency information may be indicated inmicrosecond units. In addition, wake-up delay information and turn-onlatency information may be indicated by values in a predetermined range.

The WUR capability element may include information indicating whether awireless communication terminal transmitting the WUR capability elementmay receive a variable length WUR frame. The information may be referredto as variable length WUR information. When the WUR capability elementindicates that a variable length WUR frame cannot be received, the basewireless communication terminal may transmit only the WUR framecorresponding to the fixed-length WUR frame format to the wirelesscommunication terminal that transmits the WUR capability element. TheWUR capability element may include information indicating whether awireless communication terminal transmitting the WUR capability elementcan receive a WUR frame transmitted at a predetermined reference datarate or higher. This information may be referred to as high data rateinformation. Specifically, the WUR frame can be transmitted at 62.5 Kbpsor 250 Kbps. The high data rate information may indicate whether thewireless communication terminal transmitting the WUR capability elementcan receive the WUR frame transmitted at 250 Kbps. In addition, when aWUR frame having a variable length can be transmitted only above apredetermined reference data rate, the high data rate information may beintegrated with the variable length WUR information described above.

The WUR capability element may include information indicating whetherthe wireless communication terminal transmitting the WUR capabilityelement can receive a WUR frame identifying a recipient by a group WURID in addition to a unique WUR ID. This information may be referred toas group-addressed WUR frame information. The base wirelesscommunication terminal transmits a WUR frame identifying the recipientwith a unique WUR ID to the wireless communication terminal signalingthat the WUR frame identifying the recipient with the group WUR IDcannot be received through the group-address WUR frame information. Thebase wireless communication terminal cannot transmit the WUR frameidentifying the recipient with the group WUR ID to the wirelesscommunication terminal signaling that the WUR frame identifying therecipient with the group WUR ID cannot be received through thegroup-address WUR frame information. The field indicating thegroup-address WUR frame information may be a 1-bit field.

Even a wireless communication terminal capable of receiving a WUR frameidentifying a recipient with a group WUR ID may not process a pluralityof group WUR IDs. Specifically, the number of group WUR IDs that thewireless communication terminal can store may be limited. Accordingly,the group-address WUR frame information may indicate the maximum numberof group WUR IDs that can be processed by the wireless communicationterminal that has transmitted the WUR capability element. The basewireless communication terminal may allocate a group WUR ID of a maximumnumber or less that the corresponding wireless communication terminalhas signaled through the group-address WUR frame information to thewireless communication terminal that has transmitted the WUR capabilityelement. In addition, the base wireless communication terminal cannotallocate a group WUR ID of more than the maximum number that thecorresponding wireless communication terminal has signaled through thegroup-address WUR frame information to the wireless communicationterminal that has transmitted the WUR capability element.

The WUR capability element may include information indicating whetherthe wireless communication terminal transmitting the WUR capabilityelement supports the duty-cycle operation of WURx. This information maybe referred to as duty-cycle information. The duty-cycle operation ofWURx will be described in detail with reference to FIGS. 16 and 20 to21. The wireless communication terminal signaling that the duty-cycleoperation of WURx is not supported through the duty-cycle informationmay always turn on the WURx when entering the PCR doze state. Inaddition, the corresponding wireless communication terminal may notperform a duty-cycle-related parameter exchange process with the basewireless communication terminal.

The WUR capability element may include information indicating whetherthe wireless communication terminal transmitting the WUR capabilityelement supports MIC operation. This information may be referred to asMIC information. The base wireless communication terminal may transmit aWUR frame using the MIC instead of the FCS to the wireless communicationterminal signaling to support MIC operation through MIC information. Thebase wireless communication terminal may not be allowed to transmit theWUR frame using the MIC instead of the FCS to the wireless communicationterminal signaling not to support the MIC operation through the MICinformation. A wireless communication terminal supporting MIC can detectan external attack or the like through MIC operation. In this case, thewireless communication terminal may transmit an action frame requestinga new WUR ID to the base wireless communication terminal.

The WUR capability element may include information indicating whetherthe wireless communication terminal transmitting the WUR capabilityelement supports performing a WUR operation in a channel different fromthe operating channel of the PCR. This information may be referred to asnon-primary channel WUR information. When the wireless communicationterminal signals that it does not support performing the WUR operationin a channel different from the operating channel of the PCR through thenon-primary channel WUR information, the base wireless communicationterminal may be limited to using the same channel as the operatingchannel of PCR in communication using the corresponding wirelesscommunication terminal and WUR. In this case, when the same channel asthe operating channel of the PCR cannot be used, the base wirelesscommunication terminal may change the operating channel of the PCR. Inaddition, when the same channel as the operating channel of the PCRcannot be used, the base wireless communication terminal may not allowthe corresponding wireless communication terminal to enter the PCR powersaving mode.

The WUR capability element may include information indicating whetherthe wireless communication terminal transmitting the WUR capabilityelement can perform a WUR operation in a plurality of frequency bands.This information may be referred to as WUR multiband information.Specifically, the WUR multi-band information may indicate whether thewireless communication terminal transmitting the WUR capability elementsupports each of the multi-bands. In this case, the field indicating WURmultiband information may be an n-bit field, and n may be the number offrequency bands included in the multiband. In another specificembodiment, the WUR multiband information may indicate whether thewireless communication terminal transmitting the WUR capability elementsupports an additional frequency band as well as a basic frequency band.In this case, the field indicating WUR multi-band information may be a1-bit field. Also, the plurality of frequency bands may includefrequency bands of 2.4 GHz and 5 GHz. In addition, the basic frequencyband described above may be 2.4 GHz, and the additional frequency bandmay be 5 GHz.

The WUR capability element may include information indicating whetherthe wireless communication terminal transmitting the WUR capabilityelement can receive a WUR frame encoded with a binary convolution code(BCC). This information may be referred to as BCC information. When thewireless communication terminal signals that the BCC-encoded WUR framecan be received through BCC information, the base wireless communicationterminal may transmit a BCC encoded WUR frame to the correspondingwireless communication terminal.

The WUR capability element may include information indicating the classof the wireless communication terminal that has transmitted the WURcapability element. The information may be referred to as device classinformation. In addition, the device class information may be classifiedinto a wireless communication terminal as a sink device and a sensordevice. In addition, the device class information may classify awireless communication terminal into a mobile device and a stationarydevice.

The WUR capability element may include information indicating whetherthe wireless communication terminal that has transmitted the WURcapability element can receive a WUR PPDU in which a plurality of WURframes are multiplexed to frequency division multiple access (FDMA) andtransmitted in a frequency domain in a unit channel. In this case, theunit channel is a minimum frequency bandwidth in which WUR PPDUs can betransmitted. The minimum channel bandwidth may be 20 MHz. Thisinformation may be referred to as WUR frame multiple access supportinformation. When the WUR frame multiple access support informationindicates that the wireless communication terminal does not supportreception of WUR PPDUs in which multiple WUR frames are multiplexed inthe frequency domain and transmitted, the base wireless communicationterminal may not be allowed to multiplex and transmit multiple WURframes in the WUR frame frequency domain. In this case, the basewireless communication terminal may transmit the WUR part using 13subcarriers in the center of the 20 MHz channel.

The WUR capability element may include information indicating whetherthe wireless communication terminal transmitting the WUR capabilityelement supports WUR frame transmission. This information may bereferred to as AP WUR information. PCR doze state entry of the basewireless communication terminal may be allowed only when all wirelesscommunication terminals connected to the base wireless communicationterminal indicate whether to support WUR frame transmission. Inaddition, when the base wireless communication terminal transmits AP WURinformation, the AP WUR information may indicate whether thecorresponding base wireless communication terminal supports PCR dozestate entry.

FIG. 12 shows a specific format of the WUR capability element includingthe above-described information.

Referring to FIG. 11, it has been described that the base wirelesscommunication terminal and the wireless communication terminal mayconfigure parameters related to WUR operation through action frameexchange. The WUR action frame that the wireless communication terminaltransmits to configure parameters related to WUR operation will bedescribed with reference to FIGS. 13 to 14. In addition, the WUR modeelement used for configuring parameters related to the WUR operationwill also be described.

FIG. 13 shows a specific format of a PCR power saving WUR action frameand a specific format of a WUR mode element in a wireless communicationterminal according to an embodiment of the present invention.

The wireless communication terminal may configure a parameter related tothe WUR operation by transmitting a WUR mode element to the basewireless communication terminal. As described above, the wirelesscommunication terminal may transmit the WUR mode element in the linksetup process. Also, the wireless communication terminal may transmit aWUR mode element through an action frame.

FIG. 13(a) shows a specific format of a WUR action frame according to anembodiment of the present invention. The WUR action frame may includeinformation indicating the role of the WUR action frame. Informationindicating the role of the WUR action frame may be referred to as WURaction information. The wireless communication terminal may transmit WURmode elements through the WUR action frame by setting the WUR actioninformation to WUR Setup. In this case, the WUR action frame may includea WUR Action field indicating WUR action information, a Dialog Tokenfield, and a field indicating WUR mode elements.

FIG. 13(b) shows a specific format of a WUR mode element according to anembodiment of the present invention. The WUR mode element may includeinformation indicating what stage the transmission of the WUR actionframe is in the WUR operation-related parameter configuration process.This information may be referred to as WUR setup command information.The wireless communication terminal requesting WUR operation-relatedparameter configuration may configure WUR setup command information ofthe WUR mode element as a WUR setup command indicating a WURoperation-related parameter setting request. In this case, the WUR setupcommand may be referred to as a request WUR mode command. Forconvenience of description, a wireless communication terminaltransmitting a WUR mode element, which is a WUR setup command, isreferred to as a request terminal. In addition, a wireless communicationterminal transmitting a WUR mode element in response to a WUR modeelement transmitted by the request terminal is referred to as a responseterminal. The WUR setup command that accepts the WUR operation-relatedparameter setting request may be referred to as an accept WUR modecommand.

When all WUR operation-related parameters indicated by the WUR modeelement received by the response terminal are accepted, the responseterminal may transmit to the request terminal a WUR mode element inwhich the WUR setup command is the accepted WUR mode command and the WURoperation related parameter is configured equal to the received WUR modeelement. When the response terminal does not accept any of the WURoperation-related parameters indicated by the received WUR mode element,the response terminal may suggest WUR operation-related parameters bytransmitting a WUR mode element to the request terminal. In this case,the request terminal may re-suggest parameters related to WUR operationto the request terminal according to the WUR setup command valueconfigured by the response terminal. Specifically, when the WUR setupcommand configured by the response terminal is a Dictate WUR modecommand, the request terminal may accept the parameters related to theWUR operation suggested by the response terminal through the WUR modeelement or stop configuring the WUR operation related parameter. Whenthe request terminal accepts the parameters related to WUR operationsuggested by the response terminal through the WUR mode element, therequest terminal may transmit a WUR mode element configured equal to theWUR mode element received by the WUR operation related parameter. Whenthe request terminal does not accept the parameters related to WURoperation suggested by the response terminal through the WUR modeelement, the request terminal may not transmit the WUR mode element tothe response terminal. When the WUR operation-related parameterconfiguration is stopped, the wireless communication terminal cannotenter the PCR doze state.

Specifically, when the WUR setup command configured by the responseterminal is an alternative WUR mode command, the request terminal canaccept the parameters related to the WUR operation suggested by theresponse terminal through the WUR mode element or suggest new WURoperation related parameters. When the request terminal accepts theparameters related to WUR operation suggested by the WUR mode element,the request terminal may transmit a WUR mode element in which the WURsetup command is a suggest WUR mode command or demand, and transmit aWUR mode element in which the parameters related to the suggested WURoperation are configured. The response terminal that receives thesuggest WUR mode command may transmit the WUR mode element to suggestthe WUR operation-related parameters again. The response terminalreceiving the demand WUR mode command may accept the WUR operationrelated parameter suggested by the request terminal through the WUR modeelement or stop configuring the WUR operation related parameter. Whenthe request terminal accepts the parameters related to WUR operationsuggested by the WUR mode element, the response terminal can transmit tothe request terminal a WUR mode element in which the WUR setup commandis configured as the accept WUR mode command and the WURoperation-related parameters are configured equal to the received WURmode elements. When the request terminal does not accept the parametersrelated to WUR operation suggested through the WUR mode element, theresponse terminal may transmit a WUR mode element which is a reject WURmode command. WUR operation-related parameters may be configured throughsuch operations. In addition, the wireless communication terminal andthe base wireless communication terminal may perform a WUR-based powersave operation according to the parameters related to the configured WURoperation.

The WUR mode element may include information indicating whether the WURxoperates according to a duty-cycle. This information may be referred toas duty-cycle information.

The WUR mode element may include information indicating whether the WURframe is encoded with the BCC. This information may be referred to asBCC information. When either the request terminal or the responseterminal signals that the BCC encoding is not supported by the WURcapability element, the BCC information should indicate that the WURframe is not encoded with the BCC.

The WUR mode element may include information indicating whether the WURframe is encoded with the BCC. This information may be referred to asWUR security information. If either the request terminal or the responseterminal signals that the WUR capability element does not support MIC,the WUR security information should indicate that the MIC is not used inthe WUR frame.

The WUR mode element may include information indicating whether a groupWUR ID is used in a WUR frame transmitted between a request terminal anda response terminal. This information may be referred to as group WUR IDinformation. When the group WUR ID is used, the wireless communicationterminal may transmit a WUR action frame requesting a group WUR IDallocation to the base wireless communication terminal. The wirelesscommunication terminal receiving the WUR action frame requesting thegroup WUR ID allocation may allocate the group WUR ID to the wirelesscommunication terminal transmitting the corresponding WUR action frame.In another specific embodiment, the WUR mode element may includeinformation indicating the group WUR ID together with the group WUR IDinformation.

The WUR mode element may include information indicating whether the WURID is periodically changed. This information may be referred to as WURID switch information. Periodically changing the WUR ID of the wirelesscommunication terminal may help prevent external attacks. Therefore,when there is an external attack threat, the WUR ID may be configured tobe periodically changed through the WUR ID switch information. When theWUR ID switch information indicates that the WUR ID is periodicallychanged, the wireless communication terminal may periodically request tochange the WUR ID of the wireless communication terminal. In this case,the period in which the WUR ID change is requested may be apredetermined period. In another specific embodiment, the period inwhich the WUR ID change is requested may be configured through the WURmode element. Specifically, the WUR mode element may include informationon a period in which a WUR ID change is requested. This information maybe referred to as WUR switch interval information. When the WUR IDswitch information indicates that the WUR ID is not periodicallychanged, the WUR mode element may not include WUR switch intervalinformation.

The WUR mode element may include information indicating a WUR ID to beused by the wireless communication terminal. This information may bereferred to as WUR ID information.

The WUR mode element may include information on a WUR operating channelto be used for WUR frame transmission. This information may be referredto as WUR operating channel information. WUR operating channelinformation may be indicated for each unit channel. In addition,operating channel information may be indicated by a channel number. Asdescribed above, the unit channel is a minimum frequency bandwidth inwhich WUR PPDUs can be transmitted. The minimum channel bandwidth may be20 MHz. A channel signaling that the request terminal and the responseterminal are usable in the WUR capability element may be configured as aWUR operating channel. When the wireless communication terminalindicates that the WUR capability element supports WUR frame multipleaccess, the base wireless communication terminal may signal a centersubcarrier of a channel to transmit a WUR frame in an operating channelthrough a WUR mode element.

The WUR mode element may include information indicating a parameter usedin the WUR duty-cycle operation. This information may be referred to asWUR duty-cycle parameter information. The duty-cycle parameterinformation may include information indicating a unit of the duty-cycleperiod. This information may be referred to as duty-cycle basic unitinformation. Further, the duty-cycle parameter information may includeinformation indicating the minimum awake holding time of WURx. Thisinformation may be referred to as minimum wake-up time information.Further, the duty-cycle parameter information may include informationindicating on duration of the duty cycle. This information may bereferred to as duty-cycle on duration information. Further, theduty-cycle parameter information may include information indicating theinterval of the duty cycle. This information may be referred to asduty-cycle interval information. Further, the duty-cycle parameterinformation may include information indicating the start time of theduty cycle. This information may be referred to as duty-cycle start timeinformation. In this case, duty-cycle basic unit information and minimumwake-up time information may be configured by a response terminal.Duty-cycle on duration information, duty-cycle interval information, andduty-cycle start time information may be configured by negotiation of aresponse terminal and a request terminal. When the duty-cycleinformation indicates that the WURx duty-cycle operation is not used,the WUR mode element may not include duty-cycle parameter information.

The WUR mode element may include information indicating a maximum timefor the wireless communication terminal to continuously maintain the PCRdoze state. This information may be referred to as Max WUR Mode Periodinformation. In this case, the wireless communication terminal mayrequest the base wireless communication terminal to transmit the PCRframe successfully from the time of entering the PCR doze state, beforethe time indicated by the maximum WUR all period information elapses.When the base wireless communication terminal does not receive the PCRframe from the wireless communication terminal from the time when thewireless communication terminal enters the PCR doze state until the timeindicated by the maximum WUR all period information elapses, the basewireless communication terminal may release association with thecorresponding wireless communication terminal.

The WUR mode element may include information indicating an accesscategory (AC) to be used when a wireless communication terminal accessesa channel to transmit a PS-poll frame as a WU response frame forreceiving a wake-up frame. This information may be referred to asPS-poll AC information. In the existing wireless LAN, the PS-poll framemay be used by many wireless communication terminals to access thechannel. Therefore, the AC of the PS-poll frame was configured withAC_BE with relatively low priority. When the PS-poll frame is used as aWU response frame, configuring AC of the PS-poll frame with AC_BE may beinefficient. Therefore, when a PS-poll frame is transmitted as a WUresponse frame, the AC used may be configured through a WUR modeelement. In this case, when the wireless communication terminal receivesa wake-up frame indicating the recipient of a unique WUR ID, thewireless communication terminal may be allowed to transmit the PS-pollframe as a WU response frame using AC indicated by the PS-poll ACinformation. In addition, when the wireless communication terminalreceives a wake-up frame having a fixed length, the wirelesscommunication terminal may be allowed to transmit the PS-poll frame as aWU response frame using AC indicated by the PS-poll AC information.

FIG. 14 shows a specific format of a WUR disable action frame forstopping a WUR-based power save operation according to an embodiment ofthe present invention.

The base wireless communication terminal may stop performing theWUR-based power save operation by transmitting an action frame to thewireless communication terminal performing the WUR-based power saveoperation. In this case, the action frame may be referred to as a WURdisable action frame. The WUR disable action frame may have the sameformat as the specific format of the action frame described through FIG.13(a). However, the WUR action field information may be referred to as aWUR disable action frame. In a specific embodiment, the WUR disableaction frame may include information indicating a time when theWUR-based power save operation is stopped. This information may bereferred to as WUR disable duration information. When the WUR-basedpower save operation is permanently stopped, the base wirelesscommunication terminal may configure WUR disable duration informationwith a predetermined value. In addition, the base wireless communicationterminal may transmit a wake-up frame to the wireless communicationterminal in PCR doze state to wake up the wireless communicationterminal, and then transmit a WUR disable action frame.

When the wireless communication terminal receives the WUR disable actionframe, the wireless communication terminal may stop the WUR-based powersave operation. Specifically, the wireless communication terminal maystop the WUR-based power save operation for a time indicated by the WURdisable duration information. When the time indicated by the WUR disableduration information elapses, the wireless communication terminal mayautomatically restart the WUR-based power save operation. When the WURdisable duration information indicates a predetermined value indicatingthat the WUR-based power save operation is permanently stopped, thewireless communication terminal may not be allowed to perform theWUR-based power save operation until the WUR-related parameters areconfigured again.

It has been described that the WUR ID may be changed in theabove-described embodiments. An action frame related to a WUR ID changerequest will be described with reference to FIG. 13. The action framemay be referred to as a WUR ID action frame.

FIG. 15 shows a specific format of a WUR ID action frame according to anembodiment of the present invention.

When the wireless communication terminal intends to change the WUR ID,the wireless communication terminal may transmit a WUR ID action frameto the base wireless communication terminal. Specifically, when thewireless communication terminal detects an attack from the outside whileperforming the WUR-based power save operation, the wirelesscommunication terminal may request to change the WUR ID of the wirelesscommunication terminal by transmitting a WUR ID action frame to the basewireless communication terminal through PCR. In addition, when the WURID is configured to be changed periodically in the process ofconfiguring WUR operation-related parameters, the wireless communicationterminal may request to change the WUR ID of the wireless communicationterminal by transmitting a WUR ID action frame to the base wirelesscommunication terminal through PCR.

When the wireless communication terminal requests to change the WUR IDof the wireless communication terminal, the WUR action information maybe configured as a WUR ID Switch Request. Further, the WUR ID elementmay include information indicating the WUR ID to be changed. Further,the wireless communication terminal may request to change the group WURID of the wireless communication terminal by transmitting a WUR IDaction frame to the base wireless communication terminal through PCR. Inthis case, the WUR action information may be configured as a group WURID Switch Request. In addition, the WUR ID element may includeinformation indicating a group WUR ID to be changed. Further, thewireless communication terminal may request to change the WUR ID and thegroup WUR ID together by transmitting one WUR action frame. In thiscase, the WUR ID element may include information indicating the WUR IDof the wireless communication terminal and information indicating thegroup WUR ID.

When the base wireless communication terminal receives the WUR ID actionframe from the wireless communication terminal requesting to change theWUR ID or the group WUR ID, the base wireless communication terminal maysignal the changed WUR ID or group WUR ID by transmitting a WUR IDaction frame to the wireless communication terminal. In this case, thebase wireless communication terminal may configure WUR actioninformation as a WUR ID switch response or a group WUR ID response. TheWUR ID element of the WUR ID action frame transmitted by the basewireless communication terminal may have the same format as the WUR IDelement of the WUR ID action frame transmitted by the wirelesscommunication terminal. Further, the WUR ID element may include a WUR IDor a group WUR ID to be used by the wireless communication terminal.

Also, even when the wireless communication terminal does not request tochange the WUR ID or the group WUR ID, the base wireless communicationterminal may change the WUR ID or the group WUR ID of the wirelesscommunication terminal by transmitting a WUR ID action frame to thewireless communication terminal. In this case, the base wirelesscommunication terminal may configure WUR action information as a WUR IDswitch response or a group WUR ID response. Specifically, when the basewireless communication terminal detects an external attack on thewireless communication terminal, even if the wireless communicationterminal does not request to change the WUR ID or the group WUR ID, thebase wireless communication terminal may change the WUR ID or the groupWUR ID of the wireless communication terminal by transmitting a WUR IDaction frame to the wireless communication terminal. Even if thewireless communication terminal did not request to change the WUR ID orthe group WUR ID, when the base wireless communication terminal changesthe WUR ID or the group WUR ID of the wireless communication terminal,the base wireless communication terminal may change all WUR IDs andgroup WUR IDs allocated to the corresponding wireless communicationterminal. In this case, the WUR ID action frame may include a WURID/Group WUR ID field as many as all WUR IDs and group WUR IDs allocatedto the corresponding wireless communication terminal. In addition, thebase wireless communication terminal may insert a WUR ID into a firstWUR ID/group WUR ID field among a plurality of WUR ID/group WUR IDfields.

In addition, when the group WUR ID is configured to be used in the WURoperation related parameter configuration process, the wirelesscommunication terminal may request a group WUR ID allocation bytransmitting a WUR ID action frame to the base wireless communicationterminal before entering the PCR doze state. In this case, thecorresponding WUR ID action frame may not include a WUR ID element. Whenthe base wireless communication terminal receives a WUR ID action framerequesting group WUR ID allocation from the wireless communicationterminal, the base wireless communication terminal may transmit anaction frame indicating the group WUR ID allocated to the wirelesscommunication terminal to the wireless communication terminal. In thiscase, the WUR ID element of the corresponding WUR ID action frame mayinclude a group WUR ID assigned to the corresponding wirelesscommunication terminal. In addition, the base wireless communicationterminal may allocate a plurality of group WUR IDs to the wirelesscommunication terminal. Accordingly, the WUR ID element of the WUR IDaction frame may include a plurality of group WUR IDs assigned to thecorresponding wireless communication terminal.

When the wireless communication terminal communicating with the basewireless communication terminal through PCR is out of the transmissioncoverage of the base wireless communication terminal, the wirelesscommunication terminal may determine that the connection with the basewireless communication terminal is lost (connection lost). In this case,the wireless communication terminal may perform a scan procedure forassociation with a new BSS. Specifically, the wireless communicationterminal may attempt to connect to the corresponding base wirelesscommunication terminal based on the beacon frame transmitted by the newbase wireless communication terminal. In the PCR doze state, thewireless communication terminal cannot receive the beacon frametransmitted by PCR. In addition, the wireless communication terminalcannot transmit any MAC frame through PCR unless turning on the PCRtransceiver by receiving a wake-up frame or turning on the PCRtransceiver for PCR transmission. Therefore, it may be difficult todetermine whether the wireless communication terminal in the PCR dozestate is outside the transmission coverage of the base wirelesscommunication terminal. In addition, the wireless communication terminalmay maintain the PCR doze state even though it is outside thetransmission coverage of the base wireless communication terminal. Forefficient operation of the wireless communication terminal, the basewireless communication terminal may transmit a WUR beacon frameperiodically through WUR. This will be described with reference to FIG.19.

FIG. 16 shows an operation in which a wireless communication terminalreceives a WUR beacon frame according to an embodiment of the presentinvention.

As described above, the WUR beacon frame is a type of WUR frame and maybe transmitted through a WUR PPDU. The WUR beacon frame may includeinformation on the TSF so that a wireless communication terminal in PCRdoze state can perform accurate time synchronization. In addition, theWUR beacon frame may be transmitted periodically. In this case, thetransmission period of the WUR beacon frame may be longer than thetransmission period of the PCR beacon frame. In addition, the WUR beaconframe may not include the identifier of the intended recipient of theWUR beacon frame, and may include a TXID that identifies the basewireless communication terminal transmitting the WUR beacon frame.Specifically, the Address field of the WUR beacon frame may indicate theTXID of the base wireless communication terminal transmitting the WURbeacon frame. Further, even when the wireless communication terminalperforms a WUR beacon frame, the wireless communication terminal may notturn on the PCR transceiver.

When the wireless communication terminal in PCR doze state has no datato transmit to the base wireless communication terminal, the wirelesscommunication terminal may turn off WURx based on the WUR beacon frametransmission period. Specifically, when the PCR doze state wirelesscommunication terminal has no data to be transmitted to the basewireless communication terminal, the wireless communication terminal maymaintain the WURx to be turned on in the time period during which theWUR beacon frame is transmitted and turn off the WURx in the remainingtime period. The operation of the wireless communication terminal is aWUR duty-cycle operation, and the operation mode of the wirelesscommunication terminal may be referred to as a WUR duty-cycle mode.Also, a state in which the wireless communication terminal turns offWURx may be referred to as a WUR doze state or a deep sleep state. Whenthe base wireless communication terminal has data to be transmittedthrough PCR to the wireless communication terminal in the WUR duty-cyclemode, the base wireless communication terminal may transmit a wake-upframe to the corresponding wireless communication terminal immediatelyafter transmitting the WUR beacon frame. In addition, when the basewireless communication terminal has data to be transmitted through PCRto the wireless communication terminal of the WUR duty-cycle mode, thebase wireless communication terminal may transmit a traffic indicationmap (TIM) indicating that there is data to be downlink-transmittedthrough the WUR beacon frame.

When the wireless communication terminal does not received the WURbeacon frame for a predetermined time, the wireless communicationterminal may turn on the PCR transceiver. In this case, when thewireless communication terminal does not receive the PCR beacon framefrom the base wireless communication terminal associated with thewireless communication terminal through PCR, the wireless communicationterminal may perform a scanning operation. Specifically, the wirelesscommunication terminal may transmit a probe request frame through PCR.

In the embodiment of FIG. 16, the AP periodically transmits a WUR beaconframe. In the WUR duty-cycle mode station, the WUR beacon framemaintains the WURx to be turned on according to the transmission period,and maintains the WUR doze state at other times. When the AP has data totransmit to the station through PCR, the AP transmits a wake-up frame tothe station immediately after transmitting the WUR beacon frame. Thestation receives the wake-up frame and turns on the PCR transceiver.

The WUR beacon frame does not include individual information on the WURservice, but may include information on the TSF. When the base wirelesscommunication terminal operates multiple BSS, it may be inefficient forthe base wireless communication terminal to allocate a different TXIDfor each BSS and transmit a WUR beacon frame for each BSS. Therefore,the base wireless communication terminal may configure a representativeTXID of multiple BSSIDs. The base wireless communication terminal mayinsert the configured representative TXID into the Address field of theWUR beacon frame of all BSSs operated by the base wireless communicationterminal. In this case, the representative TXID may be the TXID of thetransmitted BSS. Therefore, when the base wireless communicationterminal transmits a WUR beacon frame to a non-transmitted BSS, theaddress field of the corresponding WUR beacon frame may be configuredwith the TXID of the transmitted BSS.

The base wireless communication terminal may not allocate a TXID to thenon-transmitted BSS. When the TXID is not allocated to thenon-transmitted BSS, a method of transmitting a broadcast WUR frame to awireless communication terminal belonging to a non-transmitted BSS maybe needed. The base wireless communication terminal may configure awireless communication terminal belonging to an individualnon-transmission BSS as a group identified by one group WUR ID. Forthis, a wireless communication terminal supporting multiple BSSIDs maybe required to support one or more group WUR IDs.

In another specific embodiment, the base wireless communication terminalmay allocate a TXID to the non-transmitted BSS. In addition, the basewireless communication terminal may signal the TXID of the transmittedBSS to the non-transmitted BSS through the WUR mode element. In thisembodiment, when the base wireless communication terminal transmits abroadcast WUR frame to the wireless communication terminal belonging tothe non-transmitted BSS, the base wireless communication terminalconfigures the address field of the corresponding WUR frame as the TXIDof the corresponding non-transmitted BSS. In addition, when the wirelesscommunication terminal belonging to the non-transmitted BSS receives aWUR beacon frame in which the Address field indicates the TXID of thetransmitted BSSID, the wireless communication terminal can perform timesynchronization based on the WUR beacon frame.

In another specific embodiment, the base wireless communication terminalmay allocate a TXID to the non-transmitted BSS according to apredetermined rule. Specifically, the base wireless communicationterminal may allocate the TXID to the non-transmitted BSS based on theTXID of the transmit BSS. In a specific embodiment, the base wirelesscommunication terminal may configure the TXID of the non-transmitted BSSas a value obtained by adding a specific value to the TXID of thetransmitted BSS. In this case, when the base wireless communicationterminal signals the TXID, the base wireless communication terminal maysignal the TXID of the transmitted BSS instead of the TXID of thenon-transmitted BSS to the wireless communication terminal belonging tothe non-transmitted BSS. In addition, the base wireless communicationterminal may signal a specific value to be added to the TXID of thetransmitted BSS using the bitmap of the TIM element transmitted throughPCR. Specifically, a specific bit of the bitmap of the TIM elementtransmitted through PCR may indicate a predetermined value. In thisembodiment, the wireless communication terminal belonging to thenon-transmitted BSS may obtain a TXID of the non-transmitted BSS byadding a specific value to the TXID of the transmitted BSS.

FIG. 17 shows an operation that a wireless communication terminal wakesup according to an embodiment of the present invention.

The wireless communication terminal in PCR doze state cannot detect theframe transmitted through PCR. Therefore, when the wirelesscommunication terminal in the PCR doze state wakes up in the PCR dozestate, the corresponding wireless communication terminal may access thechannel without considering the hidden-node. Therefore, the wirelesscommunication terminal may attempt to transmit after detecting a frameor PPDU capable of setting NAV after wake-up in the PCR doze state. In aspecific embodiment, after wake-up in the PCR doze state, the wirelesscommunication terminal may hold a transmission attempt until a framecapable of setting NAV is detected or a predetermined time elapses. Inthis case, the predetermined time may be referred to as NAVSyncDelay.For example, the wireless communication terminal may wake up in the PCRdoze state, and then perform a clear channel assembly (CCA) until apredetermined time point, and then attempt transmission when framescapable of setting NAV are not detected up to a predetermined timepoint. The transmission attempt may indicate allocating the channelaccording to the channel access procedure.

In the embodiment of FIG. 17(a), the station receives a wake-up framefrom the AP in the PCR doze state. Upon receiving the wake-up frame, thestation turns on the PCR transceiver. The station may attempt to performtransmission after performing CCA when a frame capable of setting theNAV is received, or until the NAVSyncDelay elapses from the wake-uptime.

A wireless communication terminal attempting to perform transmissionafter wake-up in the PCR doze state may need to perform a backoffoperation according to an Enhanced Distributed Channel Access (EDCA)rule. In the case of the existing wireless LAN operation, the wirelesscommunication terminal receives primitive, which is MA-UNITDATA.request,from the higher layer and starts the backoff operation according to theEDCA rules. A wireless communication terminal attempting to performtransmission after wake-up in the PCR doze state may receive aMA-UNITDATA.request from a higher layer by a WUR MAC layer operatingseparately from the PCR MAC layer. Therefore, the PCR MAC layer may notreceive the MA-UNITDATA.request primitive. The WUR MAC layer may storethe MA-UNITDATA.request primitive up to the time point at which the PCRtransceiver is turned on, and deliver the MA-UNITDATA.request primitiveto the PCR MAC layer. In another specific embodiment, there may be a MACService Access Point (SAP) connecting the PCR MAC layer and the WUR MAClayer. In this case, when the PCR MAC layer wakes up, MAC SAP maydeliver MA-UNITDATA.request to the PCR MAC layer.

In the embodiment of FIG. 17(b), the station receives a wake-up framefrom the AP in the PCR doze state. Upon receiving the wake-up frame, thestation turns on the PCR transceiver. The WUR MAC layer of the stationstores the MA-UNITDATA.request primitive until the time point at whichthe PCR transceiver is turned on, and transmits the MA-UNITDATA.requestprimitive to the PCR MAC layer of the station.

FIG. 18 shows a power save operation of a wireless communicationterminal according to an embodiment of the present invention.

When a wireless communication terminal uses a power management functionin a conventional wireless LAN, the terminal may operate in two modes,that is, an active mode and a power save (PS) mode. In the active mode,the wireless communication terminal always maintains an awake state.When the wireless communication terminal is in the doze state, since thewireless communication terminal cannot receive a frame transmitted bythe base wireless communication terminal, the base wirelesscommunication terminal must be able to determine whether the wirelesscommunication terminal is in a power saving state. Therefore, the basewireless communication terminal may record in which mode among theactive mode or the PS mode the wireless communication terminal connectedto the base wireless communication terminal operates. For this, when thewireless communication terminal switches the mode of power management,the wireless communication terminal may signal a mode switch of powermanagement by setting a value of a Power Management (PM) subfield of aFrame Control field of data transmitted by the wireless communicationterminal.

After completion of the transmission sequence initiated by the wirelesscommunication terminal, the wireless communication terminal may switchthe power management mode. In addition, the wireless communicationterminal may be limited to switching a power management mode using atransmission sequence requesting an immediate response. When thewireless communication terminal transmits data in which the PM subfieldis set to 1 and receives an immediate response (ex: ACK frame, BA frame)to the corresponding data, the wireless communication terminal may starta power save mode operation. In addition, when the wirelesscommunication terminal transmits data in which the PM subfield is set to0 and receives an immediate response (ex: ACK frame, BA frame) to thecorresponding data, the wireless communication terminal may start anactive mode operation.

The existing wireless LAN standard defines a number of detailedprotocols for power save mode operation. Among many detailed protocols,normal power save mode and unscheduled automatic power save delivery(U-APSD) are protocols that do not require a separate schedulingprocess.

In the power save mode, there may be no restrictions on the uplinktransmission of the wireless communication terminal. In the power savemode, the wireless communication terminal may switch from the doze stateto the awake state at any time and attempt uplink transmission. However,when the base wireless communication terminal performs downlinktransmission, in the case where the wireless communication terminal isin a doze state, downlink transmission cannot be received. Therefore,both the normal power save mode and the U-APSD define the operation ofthe wireless communication terminal and the base wireless communicationterminal based on the downlink transmission situation.

When the wireless communication terminal switches from the active modeto the PS mode in the normal power save mode, the base wirelesscommunication terminal cannot directly transmit data to the wirelesscommunication terminal. The base wireless communication terminal storesdata to be transmitted to the wireless communication terminal in abuffer. Then, the base wireless communication terminal signals thatthere is data to be transmitted to the corresponding terminal using theTIM element of the beacon frame. The wireless communication terminal inPS mode receives a beacon frame in an awake state, and when the bitcorresponding to the AID of the wireless communication terminal of theTIM element indicates that there is data to be transmitted, the wirelesscommunication terminal may transmit the PS-poll frame to the basewireless communication terminal. In this case, the wirelesscommunication terminal may perform EDCA backoff in the AC_BE class totransmit the PS-poll frame. The base wireless communication terminalreceiving the PS-poll frame may transmit either an ACK frame or a DLBufferable Unit (BU) to the wireless communication terminal. Thewireless communication terminal receiving the ACK frame must maintainthe awake state until the base wireless communication terminal transmitsBU in the new Transmit Opportunity (TXOP). When the BU More Data fieldtransmitted by the base wireless communication terminal is activated,the wireless communication terminal should transmit the PS-poll frameagain. The wireless communication terminal needs to check the beaconframe every specified period of DTIM period.

Whether the U-APSD is used by the wireless communication terminal may beconfigured for each AC in the link setup step such as the (re)connectionstep. The AC of the wireless communication terminal using U-APSD isconfigured as a trigger-enabled AC. The corresponding AC of the baseradio communication terminal is regarded as a delivery-enabled AC. Thewireless communication terminal may not check the TIM element for ACcorresponding to the trigger-enabled AC. The wireless communicationterminal may transmit a trigger frame at any time point to open aservice period and trigger DL buffered BU transmission. In this case,the trigger frame is one of QoS data or null frames transmitted from thetrigger-enabled AC. A service period for a corresponding wirelesscommunication terminal is formed from a time point at which an immediateresponse to a trigger frame transmitted by the wireless communicationterminal is received. In the corresponding service period, the basewireless communication terminal may transmit the buffered BU. Therefore,the wireless communication terminal must maintain an awake state fromthe BU transmitted by the base wireless communication terminal to a timepoint at which an End Of Service Period (EOSP) is activated or an endtime point of a corresponding service period. When the wirelesscommunication terminal uses U-APSD for some AC, whether there is abuffered BU of the AC is not indicated by the TIM. Only the presence ofa buffered BU of AC without U-APSD is displayed in the TIM. Therefore,the wireless communication terminal should check the TIM to receive thebuffered BU of AC that does not use the U-APSD, and must follow theoperation of the normal power save mode.

In the embodiment of FIG. 18(a), the station receives data correspondingto AC_VO and AC_VI using U-APSD. The station starts a service period bytransmitting a trigger frame to the AP. The station receives an ACKframe for the trigger frame from the AP. The AP transmits QoS datacorresponding to AC_VO and QoS data corresponding to AC_VI to thestation. The station remains awake until the service period ends.

In the embodiment of FIG. 18(b), the station receives data correspondingto AC_BE through the normal PS mode. The station receives the beaconframe from the AP and checks that the bit of the TIM corresponding tothe AID of the station is activated. The station transmits a PS-pollframe to the AP, and receives a BU or ACK frame from the AP. When thestation receives the ACK frame for the PS-poll frame, the awake state ismaintained until QoS data is received from the AP. Upon receiving theQoS data, the station may transmit an ACK frame and enter the doze stateagain.

FIG. 19 shows an operation in which a wireless communication terminalinterworking a WUR-based power save mode and a general power save modeaccording to an embodiment of the present invention.

It is necessary to operate the mode conversion so that the powermanagement mode of the wireless LAN does not collide with the WUR-basedpower save mode. For this, when the WUR mode is activated, it may bedefined as indicating that the WURx is in an operational state. Inaddition, WURx may be regulated to comply with power save modeconversion. Specifically, even if the WUR mode is activated, when thewireless communication terminal is in the active mode, the wirelesscommunication terminal cannot use WURx. In addition, when the wirelesscommunication terminal is in the PS mode and the wireless communicationterminal enters the doze state, the wireless communication terminal mayuse WURx.

The wireless communication terminal in the power save mode may receive awake-up frame through WUR even when entering the doze state. Therefore,the base wireless communication terminal may induce data reception ofthe wireless communication terminal using a wake-up frame. Therefore,the wireless communication terminal that operates in the power save modeand that is in the activated WUR mode may not enter the awake stateperiodically to receive the beacon frame. Specifically, the wirelesscommunication terminal operating in the normal PS mode and the U-APSDmay not enter the awake state periodically to receive the beacon frame.This is because the base wireless communication terminal configures theservice period when protocols such as WNM Sleep mode and Target WakeTime (TWT) are used. In addition, a DMG wireless communication terminaloperating in the 60 GHz band or a wireless communication terminal of the802.11ay standard may also use a beacon frame of a different form fromthe existing beacon frame. Accordingly, the wireless communicationterminal may enter the awake state periodically to receive the beaconframe.

In the embodiment of FIG. 19, the station operates in a power save mode.As shown in FIG. 19(a), the station configures AP and WURoperation-related parameters. Then, the station turns off the PCRtransceiver and turns on the WURx. In the embodiment of FIG. 19(b),since the WURx is turned on, the station does not enter the awake stateperiodically in order to receive the beacon frame.

The WUR duty-cycle operation of the wireless communication terminal willbe described in detail with reference to FIGS. 20 to 21.

FIG. 20 shows a WUR duty-cycle operation of a wireless communicationterminal according to an embodiment of the present invention.

As described above, the wireless communication terminal may designatethe duty-cycle of the WURx, thereby maintaining the WURx in the turnedon state in negotiation with the base wireless communication terminal.In addition, in the off-duration, the wireless communication terminalcan maintain both the PCR transceiver and the WURx in a turn-off state.The wireless communication terminal may maintain the duty-cycle in theWUR-based power save mode. In the embodiment of FIG. 20(a), the stationperforms a WUR duty-cycle operation. When the AP transmits the WURbeacon-frame, the station maintains on duration to receive the WURbeacon frame. Since it takes some time for the station to turn on WURx,the station may transmit a turn-on command to the WURx before startingthe on duration in consideration of the time when the WURx is turned on.

In addition, the base wireless communication terminal and the wirelesscommunication terminal may exchange information on duty-cycleparameters. This is because the base wireless communication terminal maytransmit the WUR frame to the wireless communication terminal in the onduration. Specifically, the wireless communication terminal and the basewireless communication terminal may exchange information on duty-cycleparameters using the WUR mode element. Information on duty-cycleparameters may include at least one of the above-described duty-cyclebasic unit information, minimum wake time information, duty-cycle onduration information, duty-cycle interval information, and duty-cyclestart time information. The duty-cycle on duration may be greater thanor equal to the minimum wake time.

The period of the duty-cycle may be different for each wirelesscommunication terminal. The duty-cycle period may be configured inmultiples of the basic unit. In this case, the basic unit may bedetermined by the base wireless communication terminal. In anotherspecific embodiment, the basic unit may be a predetermined value. Inaddition, the basic unit may be configured based on the transmissionperiod of the WUR beacon frame. Since the wireless communicationterminal receives the WUR beacon frame according to the duty-cycleperiod, it may not receive all the WUR beacon frames transmitted by thebase wireless communication terminal. In addition, since the period ofthe duty-cycle may be different for each wireless communicationterminal, in order to receive the corresponding WUR beacon frame eachtime a WUR beacon frame is transmitted, the set of wirelesscommunication terminals maintaining on duration may vary.

In the on duration that the wireless communication terminal is expectedto receive the WUR beacon frame, when a WUR frame transmitted to anotherwireless communication terminal or a corresponding wirelesscommunication terminal is received, the wireless communication terminalmay consider that the WUR beacon frame is received.

In the embodiment of FIG. 20(b), the first station STA1, the secondstation STA2, and the third station STA3 operate in the WUR duty-cyclemode. The duty-cycle periods of the first station STA1, the secondstation STA2, and the third station STA3 are all different. When the APtransmits the first WUR beacon frame, the first station STA1, the secondstation STA2, and the third station STA3 receive the WUR beacon frame.When transmitting the second WUR beacon frame, the second station STA2receives the WUR beacon frame. When transmitting the third WUR beaconframe, the third station STA3 receives the WUR beacon frame. Further,when the AP transmits a wake-up frame to the second station STA2, thefirst station STA1 maintains on duration. The first station STA2 regardsthe wake-up frame transmitted to the second station STA2 as a WUR beaconframe.

FIG. 21 shows that a wireless communication terminal according to anembodiment of the present invention operates according to a More WURfield during a WUR duty-cycle operation.

The base wireless communication terminal may signal to the wirelesscommunication terminal that no further WUR frames are transmitted duringthe corresponding on duration. Information indicating that no furtherWUR frames are transmitted during the on duration may be referred to asno-more WUR frame on duration information. Specifically, the basewireless communication terminal may transmit the no-more WUR frame onduration information to the wireless communication terminal bytransmitting a WUR frame in which the More WUR field is disabled to thewireless communication terminal. In this case, the fact that the MoreWUR field is disabled may indicate that the value of the correspondingfield is 0. Further, the wireless communication terminal may transmitthe no-more WUR frame on duration information to the wirelesscommunication terminal by transmitting a WUR frame in which the sub-typeof the fixed-length WUR format is a duty-cycle end to the wirelesscommunication terminal. In this case, the base wireless communicationterminal may insert an identifier of the base wireless communicationterminal into the Address field of the WUR frame. In addition, the basewireless communication terminal can insert PTSF information into theType depend Control field of the WUR frame. In addition, when there isno data to transmit until the end of the on duration to the wirelesscommunication terminal in on duration at the time point of transmittingthe WUR frame, the base wireless communication terminal may transmit aWUR frame signaling no-more WUR frame on duration information.

When the wireless communication terminal receives the WUR framesignaling the no-more WUR frame on duration information, the wirelesscommunication terminal may determine that the WUR frame will not betransmitted to the wireless communication terminal until the next onduration. When the wireless communication terminal receives the WURframe signaling the no-more WUR frame on duration information, thewireless communication terminal may turn off WURx before thecorresponding on duration ends.

In a specific embodiment, even if the wireless communication terminalreceives a WUR frame signaling no-more WUR frame on durationinformation, the wireless communication terminal may maintain the WURxto be turned on for a minimum awake holding time. Even when the wirelesscommunication terminal receives a wake-up frame or there is data to beuplink-transmitted to the wireless communication terminal, the wirelesscommunication terminal can maintain the WURx to be turned on for aminimum awake holding time. In this case, the wireless communicationterminal may turn on the PCR transceiver in advance and start an uplinktransmission sequence after a minimum awake holding time elapses.

In another specific embodiment, the base wireless communication terminalmay signal that the WUR frame is not transmitted until the next WURbeacon frame is transmitted to the wireless communication terminal.Information indicating that the WUR frame is not transmitted until thenext WUR beacon frame is transmitted may be referred to as no-more WURframe beacon period information. Specifically, the base wirelesscommunication terminal may signal no-more WUR frame beacon periodinformation to the wireless communication terminal by transmitting a WURframe in which the More WUR field is disabled to the wirelesscommunication terminal. Further, the wireless communication terminal maysignal the no-more WUR frame beacon period information to the wirelesscommunication terminal by transmitting a WUR frame in which the sub-typeof the fixed-length WUR format is a duty-cycle end to the wirelesscommunication terminal. In this case, the base wireless communicationterminal may insert an identifier of the base wireless communicationterminal into the Address field of the WUR frame. In addition, the basewireless communication terminal can insert PTSF information into theType depend Control field of the WUR frame. In addition, when there isno data to be transmitted until the next WUR beacon frame is transmittedto all wireless communication terminals operating in the WUR mode aswell as the wireless communication terminal operating in duration on thetime point for transmitting the WUR frame, the base wirelesscommunication terminal may transmit a WUR frame signaling no-more WURframe beacon period information.

When the wireless communication terminal receives the WUR framesignaling the no-more WUR frame beacon period information, and the onduration of the wireless communication terminal before the next WURbeacon frame transmission time point ends, the wireless communicationterminal may perform an off duration operation until a next on durationstart time point.

When the wireless communication terminal receives the WUR framesignaling the no-more WUR frame beacon period information, and the onduration of the wireless communication terminal after the next WURbeacon frame transmission time point ends, the wireless communicationterminal may perform an off duration operation until the next WUR beaconframe transmission time point. In this case, the wireless communicationterminal may perform an on duration operation from the next WUR beaconframe transmission time point.

In addition, when the wireless communication terminal not performing theduty-cycle operation receives the WUR frame signaling the no-more WURframe beacon period information, the wireless communication terminal mayturn off the WURx until the next WUR beacon frame transmission timepoint. Through these operations, the wireless communication terminal canincrease power efficiency.

When the wireless communication terminal detects a signal determined tobe a wireless LAN Physical Layer Processing Data Unit (PPDU) in atypical wireless LAN, if there is no error in the preamble of the PPDU,the wireless communication terminal receives the corresponding signaluntil the end of the PPDU. After receiving the corresponding signal tothe end of the PPDU, the wireless communication terminal performsdecoding on channel coding to deliver a bitstream to the MAC layer. Thewireless communication terminal compares the FCS value at the MAC layerto determine whether an error is included in the bitstream, and obtainsa MAC frame included in the PPDU. In this way, obtaining informationfrom the PPDU after the wireless communication terminal receives theentire PPDU is that since the bit stream of the PPDU is encoded based onthe convolutional code, decoding cannot be performed until the entirePPDU is received. Also, this is because the wireless communicationterminal needs to perform additional operations such as networkallocation vector (NAV) setting by obtaining information related to theBSS and information related to a NAV from a MAC frame in which thewireless communication terminal is not a recipient.

In the case where Binary Convolution Code (BCC) is not applied whenencoding WUR PPDU, only Manchester code and repetition code can beapplied when encoding the WUR PPDU. Therefore, the wirelesscommunication terminal can sequentially decode information included inthe WUR PPDU even if the entire WUR PPDU is not received. Specifically,the wireless communication terminal may sequentially receive a pluralityof fields of the WUR frame included in the WUR PPDU. In addition, whenthe wireless communication terminal communicates using WUR, the wirelesscommunication terminal does not need to set NAV or the like inconsideration of the transmission time of another wireless communicationterminal. When the WUR frame is a frame format supported by the wirelesscommunication terminal, and the wireless communication terminal is anintended recipient of the WUR frame, the wireless communication terminalneeds to determine whether the WUR frame is valid through the FCS value.For example, when the recipient of the WUR beacon frame includes awireless communication terminal, the wireless communication terminalneeds to determine whether the WUR beacon frame is valid through the FCSvalue. Meanwhile, a wireless communication terminal other than theintended recipient of the WUR frame does not need to determine thevalidity of the WUR frame through the FCS value of the WUR frame. Inaddition, a wireless communication terminal that does not support theWUR frame format included in the received WUR PPDU does not need todetermine the validity of the corresponding WUR frame through the FCSvalue of the corresponding WUR frame. Therefore, the wirelesscommunication terminal may stop receiving the WUR part based on theinformation of the sequentially decoded WUR frame and restart the CCA.In order to stop receiving the WUR part, the wireless communicationterminal may transmit PHY.CCARESET.request from the MAC layer of the WURreceiver to the physical layer. In this case, PHY.CCARESET.request stopsreceiving the radio signal from the WUR receiver and requests that theWUR receiver restart the CCA. In addition, the wireless communicationterminal may not determine the validity of the WUR frame through the FCSvalue. Through this operation, the wireless communication terminal canreduce power consumption.

The wireless communication terminal may stop receiving the WUR framebased on information of the sequentially decoded WUR frame. Such anoperation may be applied when the wireless communication terminal doesnot support receiving BCC-encoded WUR PPDU or is configured to not useBCC encoding in the WUR operation-related parameter configurationprocess. In addition, such an operation may be applied when the preambleof the WUR PPDU indicates that BCC encoding is not used.

When the WUR frame is determined to be a WUR frame that is not supportedby the wireless communication terminal while the wireless communicationterminal receives the WUR part, the wireless communication terminal maystop receiving the corresponding WUR frame. Specifically, when it isdetermined that the WUR frame is a WUR frame that is not supported bythe wireless communication terminal, the wireless communication terminalmay stop receiving the WUR frame. In a specific embodiment, the wirelesscommunication terminal may stop receiving the WUR frame and restart CCAfor the WUR signal. In this case, the wireless communication terminalmay transmit the PHY layer PHY.CCARESET.request in the MAC layer. Inthis case, PHY.CCARESET.request stops receiving the radio signal fromthe WUR receiver and requests that the WUR receiver restart the CCA. Inaddition, when it is determined that the WUR frame is a WUR frame thatis not supported by the wireless communication terminal, the wirelesscommunication terminal may not determine the validity of thecorresponding WUR frame through the FCS value. Specifically, thewireless communication terminal may not check the field value of the WURframe. These operations will be described in detail with reference toFIGS. 22 to 23.

FIG. 22 shows a method for a wireless communication terminal to receivea WUR frame according to whether a wireless communication terminalsupports receiving a WUR frame according to an embodiment of the presentinvention.

When the Frame Control field of the MAC header of the WUR frameindicates that the protocol version of the corresponding WUR frame is aprotocol version not supported by the wireless communication terminal,the wireless communication terminal may stop receiving the correspondingWUR frame. This is because if the protocol version of the WUR frame is aprotocol version that is not supported by the wireless communicationterminal, it is highly likely that the wireless communication terminalcannot successfully decode the WUR frame even when the WUR frame isreceived. Also, a field indicating the protocol version of the WUR framemay be referred to as a Protocol Version field. The protocol version notsupported by the wireless communication terminal may include a protocolversion not supported by a standard that defines communication usingWUR.

In addition, when the Frame Control field of the MAC header of the WURframe indicates that the type or subtype of the corresponding WUR frameis a type or subtype that is not supported by the wireless communicationterminal, the wireless communication terminal may stop receiving thecorresponding WUR frame. This is because if the protocol version of theWUR frame is a type or subtype that is not supported by the wirelesscommunication terminal, it is highly likely that the wirelesscommunication terminal cannot successfully decode the WUR frame evenwhen the WUR frame is received. Also, a field indicating the type of theWUR frame may be referred to as a Type field. Also, a field indicating asubtype of the WUR frame may be referred to as a Subtype field. The typeor subtype not supported by the wireless communication terminal mayinclude a type or subtype not supported by a standard which definescommunication using WUR.

In addition, when the length field of the MAC header of the WUR frameindicates that the length of the corresponding WUR frame is a length notsupported by the wireless communication terminal, the wirelesscommunication terminal may stop receiving the corresponding WUR frame.This is because when the length of the WUR frame is a length that is notsupported by the wireless communication terminal, there is a highpossibility that the wireless communication terminal cannot successfullydecode the WUR frame even when the WUR frame is received. The length notsupported by the wireless communication terminal may include a lengthnot supported by the standard for defining communication using WUR.

In the embodiment of FIG. 22, the station WUR STA receives the WURframe. The station WUR STA does not support receiving BCC encoded WURPPDU. In addition, the station WUR STA supports receiving a WUR framewith a protocol version of 0. Therefore, when the Protocol Version fieldof the WUR frame indicates that the protocol version is 1, the stationWUR STA stops receiving the WUR frame. In addition, when the Type fieldof the WUR frame indicates a type not defined in a standard for definingcommunication using WUR, the station WUR STA stops receiving the WURframe. In addition, when the Subtype field of the WUR frame indicates asubtype not defined in a standard for defining communication using WUR,the station WUR STA stops receiving the WUR frame. In addition, when theLength field of the WUR frame indicates a length value not defined in astandard for defining communication using WUR, the station WUR STA stopsreceiving the WUR frame.

FIG. 23 shows a method of receiving a WUR frame according to whether awireless communication terminal supports reception of a WUR frame formatfor groupcast when the WUR frame received by the wireless communicationterminal according to an embodiment of the present invention is a WURframe for groupcast.

The wireless communication terminal may not support receiving the WURframe for groupcast. In addition, even when the wireless communicationterminal supports receiving the WUR frame for groupcast, it may bedetermined that the WUR frame for groupcast is not used in the processof configuring WUR operation related parameters. When it is any one ofthese cases and the wireless communication terminal receives thegroupcast WUR frame, the wireless communication terminal may stopreceiving the WUR frame. Specifically, when the Type field of the WURframe indicates a WUR frame for groupcast, the wireless communicationterminal may stop receiving the WUR frame. In the embodiment of FIG. 23,the station WUR STA does not support receiving a groupcast WUR frame.When the station WUR STA determines that the Type field or Subtype fieldof the WUR frame indicates a WUR frame for groupcast, the station WURSTA stops receiving the WUR frame.

FIG. 24 shows a method of receiving a WUR frame according to whether awireless communication terminal supports reception of a WUR frame formathaving a variable length when the WUR frame received by the wirelesscommunication terminal according to an embodiment of the presentinvention corresponds to a WUR frame format having a variable length.

The wireless communication terminal may not support the WUR frame formathaving a variable length. In this case, when the wireless communicationterminal receives a WUR frame corresponding to the variable-length WURframe format, the wireless communication terminal may stop receiving theWUR frame. Specifically, when the Type field of the WUR frame indicatesthat the WUR frame corresponds to a WUR frame format having a variablelength, the wireless communication terminal may stop receiving the WURframe. In addition, when the Type field of the WUR frame indicates thatthe WUR frame corresponds to a WUR beacon frame having a variablelength, the wireless communication terminal may stop receiving the WURframe.

In the embodiment of FIG. 24, the station WUR STA does not supportreception of a WUR frame corresponding to a WUR frame format having avariable length. When the station WUR STA determines that the Type fieldof the WUR frame indicates a WUR frame format having a variable length,the station WUR STA stops receiving the WUR frame. When the station WURSTA determines that the Type field of the WUR frame indicates a WURbeacon frame having a variable length, the station WUR STA stopsreceiving the WUR frame.

When the wireless communication terminal determines that the intendedrecipient of the corresponding WUR frame is not the wirelesscommunication terminal while receiving the WUR part, the wirelesscommunication terminal may stop receiving the corresponding WUR frame.Specifically, when the WUR frame does not indicate the WUR ID of thewireless communication terminal as a recipient of the WUR frame or thegroup WUR ID of the group included in the WUR frame, it may bedetermined that the intended recipient of the WUR frame is not awireless communication terminal. When the wireless communicationterminal determines that the intended recipient of the WUR frame is nota wireless communication terminal, the wireless communication terminalmay stop receiving the WUR frame. In a specific embodiment, the wirelesscommunication terminal may stop receiving the WUR frame and restart CCAfor the WUR signal. In this case, the wireless communication terminalmay transmit the PHY layer PHY.CCARESET.request in the MAC layer. Inthis case, PHY.CCARESET.request stops receiving the radio signal fromthe WUR receiver and requests that the WUR receiver restart the CCA. Inaddition, when the wireless communication terminal determines that theintended recipient of the WUR frame is not the wireless communicationterminal, the wireless communication terminal may not determine thevalidity of the corresponding WUR frame through the FCS value.Specifically, the wireless communication terminal may not check thefield value of the WUR frame. These operations will be described indetail with reference to FIGS. 25 to 29.

FIG. 25 shows a method of receiving a WUR frame according to whether awireless communication terminal is an intended recipient of the WURframe when the format of the WUR frame received by the wirelesscommunication terminal according to an embodiment of the presentinvention has a fixed length.

When the wireless communication terminal receives the WUR frame in thefixed length WUR frame format, and the Address field of the MAC headerof the WUR frame does not indicate the wireless communication terminal,the wireless communication terminal may stop receiving the WUR frame.When it is determined that the wireless communication terminal receivesthe WUR frame in the fixed length WUR frame format, and the Addressfield of the MAC header of the WUR frame does not indicate the wirelesscommunication terminal, the wireless communication terminal may stopreceiving the WUR frame. Based on whether the WUR ID indicated by theAddress field of the MAC header of the WUR frame is not the WUR ID ofthe wireless communication terminal, it may be determined whether theAddress field of the MAC header of the WUR frame does not indicate thewireless communication terminal. Based on whether the group WUR IDindicated by the Address field of the MAC header of the WUR frameindicates a group including a wireless communication terminal, it may bedetermined whether the Address field of the MAC header of the WUR framedoes not indicate the wireless communication terminal. Specifically, ifthe WUR ID indicated by the Address field of the MAC header of the WURframe is not the WUR ID of the wireless communication terminal, and thegroup WUR ID indicated by the Address field of the MAC header of the WURframe does not indicate the group including the wireless communicationterminal, it can be determined that the Address field of the MAC headerof the WUR frame does not indicate the wireless communication terminal.

In the embodiment of FIG. 25, the WUR ID of the station WUR STA is 1. Inaddition, the group WUR ID of the group including the station WUR STA is11. When the station WUR STA checks that the Address field indicatesthat the value of the WUR ID is 2, the station stops receiving the WURframe. In addition, when the station WUR STA checks that the Addressfield indicates that the value of the group WUR ID is 11, the stationstops receiving the WUR frame.

FIG. 26 shows a method of receiving a WUR frame according to whether thewireless communication terminal is an intended recipient of the WURframe when the format of the WUR frame of the WUR frame received by thewireless communication terminal according to an embodiment of thepresent invention has a variable length.

When the wireless communication terminal supports the reception of avariable length WUR frame format, and the WUR frame received by thewireless communication terminal corresponds to the variable length WURframe format, even if the Address field of the WUR frame does notindicate the WUR ID of the wireless communication terminal or the groupWUR ID of the group containing the wireless communication terminal, thewireless communication terminal may have to continue receiving the WURframe. Specifically, the wireless communication terminal may checkwhether the value indicated in the Length field indicates the WUR ID ofthe wireless communication terminal or the group WUR ID of the groupincluding the wireless communication terminal. If there is no subfieldindicating the WUR ID of the wireless communication terminal or thegroup WUR ID of the group including the wireless communication terminal,the wireless communication terminal may stop receiving the WUR frame. Inthis case, the wireless communication terminal may not check thevalidity of the WUR frame through the FCS value. In addition, thewireless communication terminal may determine whether the WUR framereceived by the wireless communication terminal corresponds to avariable-length WUR frame format based on the WUR frame Type field.

In the embodiment of FIG. 26, the WUR ID of the station WUR STA is 1.The WUR frame format of the WUR frame received by the station WUR STAhas a variable length. In addition, the Length field of the WUR frameindicates that three subfields indicating WUR ID are included in theFrame Body field of the WUR frame. In this case, when it is determinedthat all three subfields indicating the WUR ID of the Address field andthe Frame Body field do not indicate the WUR ID of the station WUR STA,the station WUR STA stops receiving the WUR frame.

FIG. 27 shows a variable-length WUR frame format according to anotherembodiment of the present invention.

In the variable length WUR frame format, the Frame Body field mayinclude a WUR ID or a group WUR ID. When the base wireless communicationterminal transmits a WUR frame corresponding to a variable length WURframe format, the base wireless communication terminal may insert a WURID of one of a plurality of wireless communication terminals to receivethe WUR frame in the Address field, and insert a WUR ID that identifieseach of the remaining wireless communication terminals in the Frame Bodyfield. In this case, the field indicating the WUR ID of the wirelesscommunication terminal in the Frame Body field may be referred to as aPaged STA field. The Frame Body field may include one or more Paged STAfields according to the length indicated by the Length field. The PagedSTA field may include information on the WUR ID of the wirelesscommunication terminal corresponding to the Paged STA field andadditional control information.

The first subfield of the Frame Body field may be a field indicatingcontrol information applied to all intended recipients of the WUR frame.In this case, the corresponding sub-field may be referred to as a TDControl field. In another specific embodiment, the TD Control field mayindicate another WUR ID.

When a plurality of Paged STA fields are included in the Frame Bodyfield, the base wireless communication terminal may insert a pluralityof WUR IDs from a small value WUR ID to a large value WUR ID in theorder of the Address field, the first Paged STA field, and the Paged STAfield thereafter. In this case, when the wireless communication terminalreceives a WUR frame corresponding to the variable length WUR frameformat, in the state where the Paged STA field indicating the WUR ID ofthe wireless communication terminal is not detected in the Address fieldand the Frame Body field of the WUR frame, the Address field or thePaged STA field indicating the WUR ID having a value greater than theWUR ID of the wireless communication terminal may be received. In thiscase, the wireless communication terminal may stop receiving the WURframe. In another specific embodiment, the base wireless communicationterminal may insert a plurality of WUR IDs from a large value WUR ID toa small value WUR ID in the order of Address field, first Paged STAfield, and Paged STA field thereafter. In the state where the Paged STAfield indicating the WUR ID of the wireless communication terminal isnot detected in the Frame Body field, an Address field or a Paged STAfield indicating a WUR ID having a value smaller than the WUR ID of thewireless communication terminal may be received. In this case, thewireless communication terminal may stop receiving the WUR frame.

In addition, the base wireless communication terminal may insert the WURID of the wireless communication terminal that does not requireadditional control information into the Address field. The base wirelesscommunication terminal inserts a plurality of WUR IDs from thesmall-value WUR ID to the large-value WUR ID in order, except for theWUR ID inserted in the Address field, into fields from the first PagedSTA field in the Frame Body field to the subsequent Paged STA fields. Inthis case, when the wireless communication terminal receives a WUR framecorresponding to the variable length WUR frame format, in the statewhere the Address field of the WUR frame does not indicate the WUR ID ofthe wireless communication terminal and the wireless communicationterminal does not detect the Paged STA field indicating the WUR ID ofthe wireless communication terminal in the Frame Body field of the WURframe, a Paged STA field indicating a WUR ID having a value greater thanthe WUR ID of the wireless communication terminal may be received. Inthis case, the wireless communication terminal may stop receiving theWUR frame. In another specific embodiment, the base wirelesscommunication terminal may insert a plurality of WUR IDs, except for theWUR ID inserted in the Address field, in order from a WUR ID which valueis large to a WUR ID which value is small, into fields from the firstPaged STA field in the Frame Body field to the Paged STA fieldthereafter. In this case, when the wireless communication terminalreceives a WUR frame corresponding to the variable length WUR frameformat, in the state where the Address field of the WUR frame does notindicate the WUR ID of the wireless communication terminal and thewireless communication terminal does not detect the Paged STA fieldindicating the WUR ID of the wireless communication terminal in theFrame Body field of the WUR frame, the wireless communication terminalmay receive a Paged STA field indicating a WUR ID having a value smallerthan the WUR ID of the wireless communication terminal. In this case,the wireless communication terminal may stop receiving the WUR frame.

It has been described with reference to FIG. 9 that a TXID or a groupWUR ID may be configured as the value of the Address field of the WURframe. Furthermore, it has been described that the WUR frame may betransmitted in a variable length WUR frame format. The WUR framereception operation related to this will be described with reference toFIGS. 28 to 29.

FIG. 28 shows a WUR frame format when TXID is used according to anembodiment of the present invention.

When the Address field of the WUR frame indicates TXID, the wirelesscommunication terminal may perform different WUR frame processingaccording to the format of the WUR frame. Specifically, when the Addressfield of the WUR frame indicates TXID, the wireless communicationterminal may perform different WUR frame processing according to whetherthe WUR frame corresponds to a variable length WUR frame format. In thiscase, the wireless communication terminal may determine whether the WURframe corresponds to a variable-length WUR frame format based on a valueof a field indicating whether there is a Frame Body field of the WURframe. A field indicating whether there is a frame body field may bereferred to as a frame body present field. Specifically, when theAddress field of the WUR frame indicates TXID and the WUR framecorresponds to a fixed-length WUR frame format, the wirelesscommunication terminal may determine that the corresponding WUR frame isa broadcast wake-up frame that triggers wake-up of all wirelesscommunication terminals in the PCR doze state in the BSS correspondingto the TXID. FIG. 28(a) shows a specific example of a wake-up frame thattriggers a wake-up of all wireless communication terminals in a PCR dozestate in the BSS corresponding to the TXID.

In addition, when the Address field of the WUR frame indicates TXID andthe WUR frame corresponds to a variable-length WUR frame format, thewireless communication terminal may determine that the corresponding WURframe is a wake-up frame that triggers wake-up of a plurality ofwireless communication terminals in the PCR doze state in the BSS. FIG.28(b) shows a specific example of a wake-up frame triggering wake-up ofa plurality of wireless communication terminals indicated by the FrameBody field while the Address field indicates TXID.

It may be defined that the WUR ID of the individual wirelesscommunication terminal is not configured in the Address field of the WURframe corresponding to the variable length WUR frame format. In thiscase, when the WUR frame corresponds to a variable length WUR frameformat and the Address field of the WUR frame does not indicate the TXIDof the BSS to which the wireless communication terminal belongs, thewireless communication terminal may stop receiving the corresponding WURframe. In a specific embodiment, the wireless communication terminal maystop receiving the WUR frame and restart CCA for the WUR signal. In thiscase, the wireless communication terminal may transmit the PHY layerPHY.CCARESET.request in the MAC layer. In this case,PHY.CCARESET.request stops receiving the radio signal from the WURreceiver and requests that the WUR receiver restart the CCA. This isbecause it is certain that it is not a wake-up frame transmitted by thebase wireless communication terminal connected to the wirelesscommunication terminal. When the WUR frame corresponds to a variablelength WUR frame format and the Address field of the WUR frame indicatesthe TXID of the BSS to which the wireless communication terminalbelongs, the wireless communication terminal can check whether the WURframe is transmitted without error and whether the WUR frame representsa WUR ID or a group WUR ID that identifies the wireless communicationterminal. In this case, the wireless communication terminal maydetermine whether the WUR frame is transmitted without error bygenerating an FCS value of the WUR frame or using a MIC.

In addition, when a plurality of WUR IDs are included in the Frame Bodyfield, the base wireless communication terminal may sequentially inserta plurality of WUR IDs from a WUR ID which value is small to a WUR IDwhich value is large in order into the subfields from the front subfieldto the next subfield of the Frame Body field. In this case, when thewireless communication terminal receives a WUR frame corresponding tothe variable length WUR frame format, in the state where the wirelesscommunication terminal does not detect the subfield indicating the WURID of the wireless communication terminal in the Frame Body field of theWUR frame, if a subfield indicating a WUR ID having a value greater thanthe WUR ID of the wireless communication terminal is received, thewireless communication terminal may stop receiving the WUR frame. In aspecific embodiment, the wireless communication terminal may stopreceiving the WUR frame and restart CCA for the WUR signal. In thiscase, the wireless communication terminal may transmit the PHY layerPHY.CCARESET.request in the MAC layer. In this case,PHY.CCARESET.request may stop receiving the radio signal from the WURreceiver and request that the WUR receiver restart the CCA.

In addition, when the WUR ID and the group WUR ID may be includedtogether in the Frame Body field, the base wireless communicationterminal may allocate the value of the group WUR ID to a value smallerthan the WUR ID. This is because the group WUR ID identifies a pluralityof wireless communication terminals.

In another specific embodiment, the base wireless communication terminalmay sequentially insert a plurality of WUR IDs from a WUR ID which valueis large to a WUR ID which value is small in order in to subfields fromthe front subfield of the Frame Body field to the subsequent subfields.In this case, when the wireless communication terminal receives a WURframe corresponding to the variable length WUR frame format, in thestate where the wireless communication terminal does not detect thesubfield indicating the WUR ID of the wireless communication terminal inthe Frame Body field of the WUR frame, if a subfield indicating a WUR IDhaving a value smaller than the WUR ID of the wireless communicationterminal is received, the wireless communication terminal may stopreceiving the WUR frame. In addition, when the WUR ID and the group WURID may be included together in the Frame Body field, the base wirelesscommunication terminal may allocate the value of the group WUR ID to avalue larger than the WUR ID.

Through these operations, the wireless communication terminal canprevent unnecessary receiving and decoding of a WUR frame having aseparate length, which takes a relatively long time to receive than aWUR frame corresponding to a fixed-length WUR frame format.

FIG. 29 shows a WUR frame format when a group WUR ID is used accordingto an embodiment of the present invention.

When the Address field of the WUR frame indicates the group WUR ID, thewireless communication terminal may perform different WUR frameprocessing according to the format of the WUR frame. Specifically, whenthe Address field of the WUR frame indicates group WUR ID, the wirelesscommunication terminal may perform different WUR frame processingaccording to whether the WUR frame corresponds to a variable length WURframe format. In this case, the wireless communication terminal maydetermine whether the WUR frame corresponds to a variable-length WURframe format based on a value of a field indicating whether there is aFrame Body field of the WUR frame. A field indicating whether there is aframe body field may be referred to as a frame body present field.Specifically, when the Address field of the WUR frame indicates a groupWUR ID and the WUR frame corresponds to a fixed-length WUR frame format,the wireless communication terminal may determine that the correspondingWUR frame corresponds to the group WUR ID and is a groupcast wake-upframe that triggers wake-up of all wireless communication terminals inthe PCR doze state. FIG. 29(a) shows a specific example of a groupcastwake-up frame corresponding to the group WUR ID and triggering wake-upof all wireless communication terminals in the PCR doze state.

When the group WUR ID is configured in the Address field of the WURframe corresponding to the variable length WUR frame format, the framebody field of the corresponding WUR frame may be limited to include onlythe WUR ID of the wireless communication terminal identified by thecorresponding group WUR ID. FIG. 29(b) shows a specific example of awake-up frame corresponding to a variable length wake-up frame while theAddress field indicates a group WUR ID. Therefore, when the basewireless communication terminal configures the group WUR ID in theAddress field of the WUR frame corresponding to the variable length WURframe format, the base wireless communication terminal can insert onlythe WUR ID of the wireless communication terminal identified by thecorresponding group WUR ID in the Frame Body field of the correspondingWUR frame. In this case, if the WUR frame corresponds to a variablelength WUR frame format and the Address field of the WUR frame does notindicate the group WUR ID of the group to which the wirelesscommunication terminal belongs, the wireless communication terminal maystop receiving the corresponding WUR frame. In a specific embodiment,the wireless communication terminal may stop receiving the WUR frame andrestart CCA for the WUR signal. In this case, the wireless communicationterminal may transmit the PHY layer PHY.CCARESET.request in the MAClayer. In this case, PHY.CCARESET.request may stop receiving the radiosignal from the WUR receiver and request that the WUR receiver restartthe CCA. This is because it is certain that it is not a wake-up frametransmitted to the wireless communication terminal. When the WUR framecorresponds to a variable length WUR frame format and the Address fieldof the WUR frame indicates the group WUR ID of the group to which thewireless communication terminal belongs, the wireless communicationterminal can check whether the WUR frame is transmitted without errorand whether the WUR frame represents a WUR ID that identifies thewireless communication terminal. In this case, the wirelesscommunication terminal may determine whether the WUR frame istransmitted without error by generating an FCS value of the WUR frame orusing a MIC.

Through these operations, the wireless communication terminal canprevent unnecessary receiving of a WUR frame having a separate length,which takes a relatively long time to receive than a WUR framecorresponding to a fixed-length WUR frame format and decoding of thecorresponding WUR frame.

FIG. 30 shows a method for a wireless communication terminal to receivea WUR frame according to a value of a More WUR field according to anembodiment of the present invention.

As described with reference to FIG. 21, when the wireless communicationterminal performing the WUR duty-cycle operation receives the WUR framein which the More WUR field is disabled, the wireless communicationterminal may stop operation in the corresponding on duration.Specifically, when the wireless communication terminal performing theWUR duty-cycle operation receives the WUR frame in which the More WURfield is disabled, the wireless communication terminal may stop the onduration operation before the corresponding on duration is ended. Forthis operation, the wireless communication terminal needs to determinewhether the value of the More WUR field decoded by the wirelesscommunication terminal is valid. Therefore, even if it is clear that thewireless communication terminal is not the intended recipient of the WURframe received by the wireless communication terminal, when the More WURfield of the corresponding WUR frame is disabled, if it is determinedthat the wireless communication terminal is not the intended recipientof the WUR frame received, the wireless communication terminal may notbe allowed to stop receiving the WUR frame. In this case, the wirelesscommunication terminal may receive the WUR frame to the end anddetermine the validity of the WUR frame through the FCS value.

In the embodiment of FIG. 30(a), the station WUR STA is performing a WURduty-cycle operation. In addition, the WUR ID of the station WUR STAis 1. When the station WUR STA receives the WUR frame, the station WURSTA is performing an on duration operation. In this case, the value ofthe More WUR field of the WUR frame is 0, indicating that the More WURfield is disabled. The station WUR STA receives the WUR frame to the endeven when the Address field of the WUR frame indicates 2 different fromthe WUR ID of the station WUR STA. In addition, the station WUR STAgenerates an FCS value based on the field value of the WUR frame. Thestation WUR STA verifies the validity of the WUR frame by comparing thegenerated FCS value with the value of the FCS field.

However, when the More WUR field of the WUR frame received by thewireless communication terminal is activated, and it is clear that thewireless communication terminal is not the intended recipient of thecorresponding WUR frame, the wireless communication terminal may stopreceiving the WUR frame. This is because the wireless communicationterminal does not need to determine whether the value of the More WURfield is valid.

In the embodiment of FIG. 30(b), the station WUR STA is performing a WURduty-cycle operation. In addition, the WUR ID of the station WUR STAis 1. When the station WUR STA receives the WUR frame, the station WURSTA is performing an on duration operation. In this case, the value ofthe More WUR field of the WUR frame is 1, indicating that the More WURfield is activated. The station WUR STA indicates that the Address fieldof the WUR frame is different from the WUR ID of the station WUR STA.Since the station WUR STA does not need to determine whether the valueof the More WUR field is valid, when the station WUR STA determines thatit is clear that the Address field does not indicate the station WURSTA, the station WUR STA stops receiving the WUR frame.

FIG. 31 is a flowchart illustrating an operation in which a wirelesscommunication terminal receives a WUR frame according to an embodimentof the present invention.

The wireless communication terminal may sequentially receive a pluralityof fields of the WUR frame included in the WUR PPDU (S3101). Asdescribed above, when encoding that changes the order of data includedin the WUR frame, such as BCC coding, is not applied, the wirelesscommunication terminal may sequentially receive a plurality of fields ofthe WUR frame. When BCC coding is not applied to the WUR frame, it maybe a case where the wireless communication terminal does not support thereception of the BCC coded WUR frame. In addition, when BCC coding isnot applied to the WUR frame, it may be a case where BCC coding isdetermined not to be used in the process of configuring parametersrelated to WUR operation of the wireless communication terminal and thebase wireless communication terminal.

When the wireless communication terminal determines that a plurality offields satisfy a predetermined condition, the wireless communicationterminal may stop receiving the WUR frame without determining whetherthe values of the plurality of fields are valid (S3103). Thepredetermined condition may include a case where the wirelesscommunication terminal is not an intended recipient of the WUR frame.The wireless communication terminal may determine whether the wirelesscommunication terminal is not an intended recipient of the WUR framebased on whether the WUR frame does not indicate the identifier of thewireless communication terminal as a recipient of the WUR frame. Inaddition, the wireless communication terminal may determine whether thewireless communication terminal is not an intended recipient of the WURframe based on whether the WUR frame does not indicate an identifier ofa group including the wireless communication terminal as a recipient ofthe WUR frame. Specifically, when the WUR frame does not indicate theidentifier of the wireless communication terminal as a recipient of theWUR frame, and the WUR frame does not indicate the identifier of thegroup including the wireless communication terminal as a recipient ofthe WUR frame, the wireless communication terminal may determine thatthe wireless communication terminal is not the intended recipient of theWUR frame. In a specific embodiment, the plurality of fields of the WURframe may include a plurality of fields indicating a wirelesscommunication terminal to receive the WUR frame. For convenience ofdescription, each of a plurality of fields indicating a wirelesscommunication terminal to receive the WUR frame is referred to as areception terminal field. In this case, the plurality of receptionterminal fields may be arranged in the WUR frame based on the size orderof the identifier indicated by the reception terminal field. Thewireless communication terminal may compare the decoded receptionterminal field value with the WUR ID value of the wireless communicationterminal. The wireless communication terminal may determine that the WURwireless communication terminal is not the intended recipient of the WURframe based on the comparison result. The specific operation of thewireless communication terminal may be the same as that in theembodiments described with reference to FIGS. 25 to 29.

When it is necessary to determine whether any one of the plurality offields is valid even if the wireless communication terminal is not theintended recipient of the WUR frame, the wireless communication terminalmay not stop receiving the WUR frame. Specifically, when the More WURfield of the WUR frame received by the wireless communication terminaloperating in the WUR duty-cycle mode is disabled, the wirelesscommunication terminal may receive all fields included in the WUR frameeven when the intended recipient of the corresponding WUR frame is not awireless communication terminal.

The predetermined condition may include a case where the wirelesscommunication terminal does not support the reception of the WUR frame.When the WUR frame has a length not supported by the wirelesscommunication terminal, the wireless communication terminal maydetermine that the wireless communication terminal does not support thereception of the WUR frame. When the WUR frame has a length notsupported by the wireless communication terminal, the wirelesscommunication terminal may determine that the wireless communicationterminal does not support the reception of the WUR frame. When the WURframe is a type not supported by the wireless communication terminal,the wireless communication terminal may determine that the wirelesscommunication terminal does not support the reception of the WUR frame.When the WUR frame indicates a protocol not supported by the wirelesscommunication terminal, the wireless communication terminal maydetermine that the wireless communication terminal does not support thereception of the WUR frame. The specific operation of the wirelesscommunication terminal may be the same as that in the embodimentsdescribed with reference to FIGS. 22 to 24.

The wireless communication terminal may stop receiving the WUR frame bytransmitting a command to stop receiving the modulated wireless signalaccording to the second modulation method from the MAC layer to thephysical layer. In a specific embodiment, the wireless communicationterminal may stop receiving the WUR frame and restart CCA for the WURsignal. In this case, the wireless communication terminal may transmitthe PHY.CCARESET.request from the MAC layer of the WUR receiver to thephysical layer. In this case, PHY.CCARESET.request stops receiving theradio signal from the WUR receiver and requests that the WUR receiverrestart the CCA. In addition, the wireless communication terminal maynot determine the validity of the WUR frame through the FCS value.

When the wireless communication terminal determines that predeterminedconditions for a plurality of fields are satisfied, the wirelesscommunication terminal may stop receiving the WUR frame withoutdetermining whether the values of the plurality of fields of the WURframe are valid through the FCS values generated based on the values ofthe plurality of fields. In addition, when the wireless communicationterminal determines that predetermined conditions for a plurality offields are satisfied, the wireless communication terminal may stopreceiving the WUR frame without determining whether values of aplurality of fields of the WUR frame are valid through the MIC.

The above-mentioned description of the present disclosure is forillustrative purposes only, and it will be understood that those ofordinary skill in the art to which the present disclosure belongs maymake changes to the present disclosure without altering the technicalideas or essential characteristics of the present disclosure and theinvention may be easily modified in other specific forms. Therefore, theembodiments described above are illustrative and are not restricted inall aspects. For example, each component described as a single entitymay be distributed and implemented, and likewise, components describedas being distributed may also be implemented in an associated fashion.

The scope of the present disclosure is defined by the appended claimsrather than the above detailed description, and all changes ormodifications derived from the meaning and range of the appended claimsand equivalents thereof are to be interpreted as being included withinthe scope of present disclosure.

1-20. (canceled)
 21. A wireless communication terminal to communicatewirelessly, the terminal comprising: a first wireless transceiverconfigured to transmit and receive signals modulated by a firstmodulation method; a second wireless receiver configured to receive asignal modulated by a second modulation method which uses On-Off Keyingand is different from the first modulation method; and a processor,wherein the processor is configured to: sequentially receive a pluralityof fields of a wake-up radio (WUR) frame included in a WUR physicallayer processing data unit (PPDU) transmitted by the second modulationmethod, and when one or more predetermined conditions for the pluralityof fields is satisfied, stop receiving the WUR frame without determiningwhether values of the plurality of fields are valid, wherein the one ormore predetermined conditions comprise a case where the wirelesscommunication terminal is not an intended recipient of the WUR frame.22. The wireless communication terminal of claim 21, wherein theprocessor is configured to determine whether the wireless communicationterminal is not the intended recipient of the WUR frame based on whetherthe WUR frame does not indicate an identifier of the wirelesscommunication terminal as the recipient of the WUR frame.
 23. Thewireless communication terminal of claim 22, wherein the plurality offields of the WUR frame comprise a plurality of reception terminalfields indicating a wireless communication terminal to receive the WURframe, and the plurality of reception terminal fields are located in theWUR frame based on the order of the size of the value of the identifierof the wireless communication terminal indicated by each of theplurality of reception terminal fields, wherein the processor isconfigured to compare the value of the received reception terminal fieldwith the value of the identifier of the wireless communication terminaland determine whether the wireless communication terminal is not theintended recipient of the WUR frame based on a result of the comparison.24. The wireless communication terminal of claim 21, wherein theprocessor is configured to determine whether the wireless communicationterminal is not the intended recipient of the WUR frame based on whetherthe WUR frame does not indicate an identifier of a group including thewireless communication terminal as the recipient of the WUR frame. 25.The wireless communication terminal of claim 21, wherein when it isnecessary to determine whether any one of the plurality of fields isvalid even if the wireless communication terminal is not the intendedrecipient of the WUR frame, the processor is configured not to stopreceiving the WUR frame.
 26. The wireless communication terminal ofclaim 21, wherein the one or more predetermined conditions comprise acase where the wireless communication terminal does not support thereception of the WUR frame.
 27. The wireless communication terminal ofclaim 26, wherein when the WUR frame has a length not supported by thewireless communication terminal, the processor is configured todetermine that the wireless communication terminal does not support thereception of the WUR frame.
 28. The wireless communication terminal ofclaim 26, wherein when the WUR frame has a length not supported by thewireless communication terminal, the processor is configured todetermine that the wireless communication terminal does not support thereception of the WUR frame.
 29. The wireless communication terminal ofclaim 26, wherein when the WUR frame is a type not supported by thewireless communication terminal, the processor is configured todetermine that the wireless communication terminal does not support thereception of the WUR frame.
 30. The wireless communication terminal ofclaim 26, wherein when the WUR frame indicates a protocol not supportedby the wireless communication terminal, the processor is configured todetermine that the wireless communication terminal does not support thereception of the WUR frame.
 31. The wireless communication terminal ofclaim 21, wherein when the one or more predetermined conditions for theplurality of fields are satisfied, the processor stops receiving the WURframe without determining whether values of the plurality of fields ofthe WUR frame are valid through a frame check sequence (FCS) valuegenerated based on the values of the plurality of fields.
 32. Thewireless communication terminal of claim 21, wherein the processor isconfigured to stop receiving the radio signal modulated according to thesecond modulation method, and stops receiving the WUR frame bytransmitting a command for requesting to restart clear channelassessment (CCA) from a medium access control (MAC) layer to a physicallayer.
 33. A method of operating a wireless communication terminal forwirelessly transmitting and receiving a signal modulated by a firstmodulation method, and receiving a signal modulated by a secondmodulation method which uses On-Off Keying and is different from thefirst modulation method, the method comprising: sequentially receiving aplurality of fields of a wake-up radio (WUR) frame included in a WURphysical layer processing data unit (PPDU) transmitted by the secondmodulation method, and when one or more predetermined conditions for theplurality of fields are satisfied, stopping receiving the WUR framewithout determining whether values of the plurality of fields are valid,wherein the one or more predetermined conditions comprise a case wherethe wireless communication terminal is not an intended recipient of theWUR frame.
 34. The method of claim 33, wherein the stopping thereceiving the WUR frame comprises determining whether the wirelesscommunication terminal is not the intended recipient of the WUR framebased on whether the WUR frame does not indicate an identifier of thewireless communication terminal as the recipient of the WUR frame. 35.The method of claim 34, wherein the plurality of fields of the WUR framecomprise a plurality of reception terminal fields indicating a wirelesscommunication terminal to receive the WUR frame, and the plurality ofreception terminal fields are located in the WUR frame based on theorder of the size of the value of the identifier of the wirelesscommunication terminal indicated by each of the plurality of receptionterminal fields, wherein the stopping the receiving the WUR framecomprises comparing the value of the received reception terminal fieldwith the value of the identifier of the wireless communication terminaland determining whether the wireless communication terminal is not theintended recipient of the WUR frame based on a result of the comparison.36. The method of claim 34, wherein the stopping the receiving the WURframe comprises determining whether the wireless communication terminalis not the intended recipient of the WUR frame based on whether the WURframe does not indicate an identifier of a group including the wirelesscommunication terminal as the recipient of the WUR frame.
 37. The methodof claim 34, wherein the stopping the receiving the WUR frame comprisesnot stopping receiving the WUR frame when it is necessary to determinewhether any one of the plurality of fields is valid even if the wirelesscommunication terminal is not the intended recipient of the WUR frame.38. The method of claim 33, wherein the one or more predeterminedconditions comprise a case where the wireless communication terminaldoes not support the reception of the WUR frame.